Inject Javascript in GWT - java

When I inject javascript this way:
ScriptInjector.fromString("var WRInitTime=(new Date()).getTime();").inject();
ScriptInjector.fromString(Resources.instance.clicktaleScript().getText()).inject();
I can see that the script injected was in a IFRAME. What is the GWT approach in injecting Javascript code? Considering that the pages are "Ajax" or Dynamic. The goal is to make Clicktale script be able to record browser events just like how it works for normal HTML pages, making this work with Dynamic website with Ajax data is quite hard.
The actual JS Script are:
<!-- ClickTale Top part -->
<script type="text/javascript">
var WRInitTime=(new Date()).getTime();
</script>
<!-- ClickTale end of Top part -->
and
<script type='text/javascript'>
// The ClickTale Balkan Tracking Code may be programmatically customized using hooks:
//
// function ClickTalePreRecordingHook() { /* place your customized code here */ }
//
// For details about ClickTale hooks, please consult the wiki page http://wiki.clicktale.com/Article/Customizing_code_version_2
document.write(unescape("%3Cscript%20src='"+
(document.location.protocol=='https:'?
"https://clicktalecdn.sslcs.cdngc.net/www02/ptc/1239e635-ed5c-4c26-81a7-5eedf55952f0.js":
"http://cdn.clicktale.net/www02/ptc/1239e635-ed5c-4c26-81a7-5eedf55952f0.js")+"'%20type='text/javascript'%3E%3C/script%3E"));
</script>
<!-- ClickTale end of Bottom part -->

I am not 100% sure, what your problem is, but if you want to access the same frame as the GWT Application you will need to set the correct Window object:
ScriptInjector s= ScriptInjector.fromString("var WRInitTime=(new Date()).getTime();");
s.setWindow(ScriptInjector.TOP_WINDOW);
s.inject();
http://www.gwtproject.org/javadoc/latest/com/google/gwt/core/client/ScriptInjector.FromString.html

Related

response.sendRediect fail to work. [duplicate]

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How can I redirect the user from one page to another using jQuery or pure JavaScript?
One does not simply redirect using jQuery
jQuery is not necessary, and window.location.replace(...) will best simulate an HTTP redirect.
window.location.replace(...) is better than using window.location.href, because replace() does not keep the originating page in the session history, meaning the user won't get stuck in a never-ending back-button fiasco.
If you want to simulate someone clicking on a link, use
location.href
If you want to simulate an HTTP redirect, use location.replace
For example:
// similar behavior as an HTTP redirect
window.location.replace("http://stackoverflow.com");
// similar behavior as clicking on a link
window.location.href = "http://stackoverflow.com";
WARNING: This answer has merely been provided as a possible solution; it is obviously not the best solution, as it requires jQuery. Instead, prefer the pure JavaScript solution.
$(location).prop('href', 'http://stackoverflow.com')
Standard "vanilla" JavaScript way to redirect a page
window.location.href = 'newPage.html';
Or more simply: (since window is Global)
location.href = 'newPage.html';
If you are here because you are losing HTTP_REFERER when redirecting, keep reading:
(Otherwise ignore this last part)
The following section is for those using HTTP_REFERER as one of many security measures (although it isn't a great protective measure). If you're using Internet Explorer 8 or lower, these variables get lost when using any form of JavaScript page redirection (location.href, etc.).
Below we are going to implement an alternative for IE8 & lower so that we don't lose HTTP_REFERER. Otherwise, you can almost always simply use window.location.href.
Testing against HTTP_REFERER (URL pasting, session, etc.) can help tell whether a request is legitimate.
(Note: there are also ways to work-around / spoof these referrers, as noted by droop's link in the comments)
Simple cross-browser testing solution (fallback to window.location.href for Internet Explorer 9+ and all other browsers)
Usage: redirect('anotherpage.aspx');
function redirect (url) {
var ua = navigator.userAgent.toLowerCase(),
isIE = ua.indexOf('msie') !== -1,
version = parseInt(ua.substr(4, 2), 10);
// Internet Explorer 8 and lower
if (isIE && version < 9) {
var link = document.createElement('a');
link.href = url;
document.body.appendChild(link);
link.click();
}
// All other browsers can use the standard window.location.href (they don't lose HTTP_REFERER like Internet Explorer 8 & lower does)
else {
window.location.href = url;
}
}
There are lots of ways of doing this.
// window.location
window.location.replace('http://www.example.com')
window.location.assign('http://www.example.com')
window.location.href = 'http://www.example.com'
document.location.href = '/path'
// window.history
window.history.back()
window.history.go(-1)
// window.navigate; ONLY for old versions of Internet Explorer
window.navigate('top.jsp')
// Probably no bueno
self.location = 'http://www.example.com';
top.location = 'http://www.example.com';
// jQuery
$(location).attr('href','http://www.example.com')
$(window).attr('location','http://www.example.com')
$(location).prop('href', 'http://www.example.com')
This works for every browser:
window.location.href = 'your_url';
It would help if you were a little more descriptive in what you are trying to do. If you are trying to generate paged data, there are some options in how you do this. You can generate separate links for each page that you want to be able to get directly to.
<a href='/path-to-page?page=1' class='pager-link'>1</a>
<a href='/path-to-page?page=2' class='pager-link'>2</a>
<span class='pager-link current-page'>3</a>
...
Note that the current page in the example is handled differently in the code and with CSS.
If you want the paged data to be changed via AJAX, this is where jQuery would come in. What you would do is add a click handler to each of the anchor tags corresponding to a different page. This click handler would invoke some jQuery code that goes and fetches the next page via AJAX and updates the table with the new data. The example below assumes that you have a web service that returns the new page data.
$(document).ready( function() {
$('a.pager-link').click( function() {
var page = $(this).attr('href').split(/\?/)[1];
$.ajax({
type: 'POST',
url: '/path-to-service',
data: page,
success: function(content) {
$('#myTable').html(content); // replace
}
});
return false; // to stop link
});
});
I also think that location.replace(URL) is the best way, but if you want to notify the search engines about your redirection (they don't analyze JavaScript code to see the redirection) you should add the rel="canonical" meta tag to your website.
Adding a noscript section with a HTML refresh meta tag in it, is also a good solution. I suggest you to use this JavaScript redirection tool to create redirections. It also has Internet Explorer support to pass the HTTP referrer.
Sample code without delay looks like this:
<!-- Place this snippet right after opening the head tag to make it work properly -->
<!-- This code is licensed under GNU GPL v3 -->
<!-- You are allowed to freely copy, distribute and use this code, but removing author credit is strictly prohibited -->
<!-- Generated by http://insider.zone/tools/client-side-url-redirect-generator/ -->
<!-- REDIRECTING STARTS -->
<link rel="canonical" href="https://yourdomain.example/"/>
<noscript>
<meta http-equiv="refresh" content="0;URL=https://yourdomain.example/">
</noscript>
<!--[if lt IE 9]><script type="text/javascript">var IE_fix=true;</script><![endif]-->
<script type="text/javascript">
var url = "https://yourdomain.example/";
if(typeof IE_fix != "undefined") // IE8 and lower fix to pass the http referer
{
document.write("redirecting..."); // Don't remove this line or appendChild() will fail because it is called before document.onload to make the redirect as fast as possible. Nobody will see this text, it is only a tech fix.
var referLink = document.createElement("a");
referLink.href = url;
document.body.appendChild(referLink);
referLink.click();
}
else { window.location.replace(url); } // All other browsers
</script>
<!-- Credit goes to http://insider.zone/ -->
<!-- REDIRECTING ENDS -->
But if someone wants to redirect back to home page then he may use the following snippet.
window.location = window.location.host
It would be helpful if you have three different environments as development, staging, and production.
You can explore this window or window.location object by just putting these words in Chrome Console or Firebug's Console.
JavaScript provides you many methods to retrieve and change the current URL which is displayed in browser's address bar. All these methods uses the Location object, which is a property of the Window object. You can create a new Location object that has the current URL as follows..
var currentLocation = window.location;
Basic Structure of a URL
<protocol>//<hostname>:<port>/<pathname><search><hash>
Protocol -- Specifies the protocol name be used to access the resource on the Internet. (HTTP (without SSL) or HTTPS (with SSL))
hostname -- Host name specifies the host that owns the resource. For example, www.stackoverflow.com. A server provides services using the name of the host.
port -- A port number used to recognize a specific process to which an Internet or other network message is to be forwarded when it arrives at a server.
pathname -- The path gives info about the specific resource within the host that the Web client wants to access. For example, stackoverflow.com/index.html.
query -- A query string follows the path component, and provides a string of information that the resource can utilize for some purpose (for example, as parameters for a search or as data to be processed).
hash -- The anchor portion of a URL, includes the hash sign (#).
With these Location object properties you can access all of these URL components
hash -Sets or returns the anchor portion of a URL.
host -Sets
or returns the hostname and port of a URL.
hostname -Sets or
returns the hostname of a URL.
href -Sets or returns the entire
URL.
pathname -Sets or returns the path name of a URL.
port -Sets or returns the port number the server uses for a URL.
protocol -Sets or returns the protocol of a URL.
search -Sets
or returns the query portion of a URL
Now If you want to change a page or redirect the user to some other page you can use the href property of the Location object like this
You can use the href property of the Location object.
window.location.href = "http://www.stackoverflow.com";
Location Object also have these three methods
assign() -- Loads a new document.
reload() -- Reloads the current document.
replace() -- Replaces the current document with a new one
You can use assign() and replace methods also to redirect to other pages like these
location.assign("http://www.stackoverflow.com");
location.replace("http://www.stackoverflow.com");
How assign() and replace() differs -- The difference between replace() method and assign() method(), is that replace() removes the URL of the current document from the document history, means it is not possible to use the "back" button to navigate back to the original document. So Use the assign() method if you want to load a new document, andwant to give the option to navigate back to the original document.
You can change the location object href property using jQuery also like this
$(location).attr('href',url);
And hence you can redirect the user to some other url.
Basically jQuery is just a JavaScript framework and for doing some of the things like redirection in this case, you can just use pure JavaScript, so in that case you have 3 options using vanilla JavaScript:
1) Using location replace, this will replace the current history of the page, means that it is not possible to use the back button to go back to the original page.
window.location.replace("http://stackoverflow.com");
2) Using location assign, this will keep the history for you and with using back button, you can go back to the original page:
window.location.assign("http://stackoverflow.com");
3) I recommend using one of those previous ways, but this could be the third option using pure JavaScript:
window.location.href="http://stackoverflow.com";
You can also write a function in jQuery to handle it, but not recommended as it's only one line pure JavaScript function, also you can use all of above functions without window if you are already in the window scope, for example window.location.replace("http://stackoverflow.com"); could be location.replace("http://stackoverflow.com");
Also I show them all on the image below:
Should just be able to set using window.location.
Example:
window.location = "https://stackoverflow.com/";
Here is a past post on the subject: How do I redirect to another webpage?
Before I start, jQuery is a JavaScript library used for DOM manipulation. So you should not be using jQuery for a page redirect.
A quote from Jquery.com:
While jQuery might run without major issues in older browser versions,
we do not actively test jQuery in them and generally do not fix bugs
that may appear in them.
It was found here:
https://jquery.com/browser-support/
So jQuery is not an end-all and be-all solution for backwards compatibility.
The following solution using raw JavaScript works in all browsers and have been standard for a long time so you don't need any libraries for cross browser support.
This page will redirect to Google after 3000 milliseconds
<!DOCTYPE html>
<html>
<head>
<title>example</title>
</head>
<body>
<p>You will be redirected to google shortly.</p>
<script>
setTimeout(function(){
window.location.href="http://www.google.com"; // The URL that will be redirected too.
}, 3000); // The bigger the number the longer the delay.
</script>
</body>
</html>
Different options are as follows:
window.location.href="url"; // Simulates normal navigation to a new page
window.location.replace("url"); // Removes current URL from history and replaces it with a new URL
window.location.assign("url"); // Adds new URL to the history stack and redirects to the new URL
window.history.back(); // Simulates a back button click
window.history.go(-1); // Simulates a back button click
window.history.back(-1); // Simulates a back button click
window.navigate("page.html"); // Same as window.location="url"
When using replace, the back button will not go back to the redirect page, as if it was never in the history. If you want the user to be able to go back to the redirect page then use window.location.href or window.location.assign. If you do use an option that lets the user go back to the redirect page, remember that when you enter the redirect page it will redirect you back. So put that into consideration when picking an option for your redirect. Under conditions where the page is only redirecting when an action is done by the user then having the page in the back button history will be okay. But if the page auto redirects then you should use replace so that the user can use the back button without getting forced back to the page the redirect sends.
You can also use meta data to run a page redirect as followed.
META Refresh
<meta http-equiv="refresh" content="0;url=http://evil.example/" />
META Location
<meta http-equiv="location" content="URL=http://evil.example" />
BASE Hijacking
<base href="http://evil.example/" />
Many more methods to redirect your unsuspecting client to a page they may not wish to go can be found on this page (not one of them is reliant on jQuery):
https://code.google.com/p/html5security/wiki/RedirectionMethods
I would also like to point out, people don't like to be randomly redirected. Only redirect people when absolutely needed. If you start redirecting people randomly they will never go to your site again.
The next paragraph is hypothetical:
You also may get reported as a malicious site. If that happens then when people click on a link to your site the users browser may warn them that your site is malicious. What may also happen is search engines may start dropping your rating if people are reporting a bad experience on your site.
Please review Google Webmaster Guidelines about redirects:
https://support.google.com/webmasters/answer/2721217?hl=en&ref_topic=6001971
Here is a fun little page that kicks you out of the page.
<!DOCTYPE html>
<html>
<head>
<title>Go Away</title>
</head>
<body>
<h1>Go Away</h1>
<script>
setTimeout(function(){
window.history.back();
}, 3000);
</script>
</body>
</html>
If you combine the two page examples together you would have an infant loop of rerouting that will guarantee that your user will never want to use your site ever again.
var url = 'asdf.html';
window.location.href = url;
You can do that without jQuery as:
window.location = "http://yourdomain.com";
And if you want only jQuery then you can do it like:
$jq(window).attr("location","http://yourdomain.com");
This works with jQuery:
$(window).attr("location", "http://google.fr");
# HTML Page Redirect Using jQuery/JavaScript Method
Try this example code:
function YourJavaScriptFunction()
{
var i = $('#login').val();
if (i == 'login')
window.location = "Login.php";
else
window.location = "Logout.php";
}
If you want to give a complete URL as window.location = "www.google.co.in";.
Original question: "How to redirect using jQuery?", hence the answer implements jQuery >> Complimentary usage case.
To just redirect to a page with JavaScript:
window.location.href = "/contact/";
Or if you need a delay:
setTimeout(function () {
window.location.href = "/contact/";
}, 2000); // Time in milliseconds
jQuery allows you to select elements from a web page with ease. You can find anything you want on a page and then use jQuery to add special effects, react to user actions, or show and hide content inside or outside the element you have selected. All these tasks start with knowing how to select an element or an event.
$('a,img').on('click',function(e){
e.preventDefault();
$(this).animate({
opacity: 0 //Put some CSS animation here
}, 500);
setTimeout(function(){
// OK, finished jQuery staff, let's go redirect
window.location.href = "/contact/";
},500);
});
Imagine someone wrote a script/plugin with 10000 lines of code. With jQuery you can connect to this code with just a line or two.
So, the question is how to make a redirect page, and not how to redirect to a website?
You only need to use JavaScript for this. Here is some tiny code that will create a dynamic redirect page.
<script>
var url = window.location.search.split('url=')[1]; // Get the URL after ?url=
if( url ) window.location.replace(url);
</script>
So say you just put this snippet into a redirect/index.html file on your website you can use it like so.
http://www.mywebsite.com/redirect?url=http://stackoverflow.com
And if you go to that link it will automatically redirect you to stackoverflow.com.
Link to Documentation
And that's how you make a Simple redirect page with JavaScript
Edit:
There is also one thing to note. I have added window.location.replace in my code because I think it suits a redirect page, but, you must know that when using window.location.replace and you get redirected, when you press the back button in your browser it will not got back to the redirect page, and it will go back to the page before it, take a look at this little demo thing.
Example:
The process: store home => redirect page to google => google
When at google: google => back button in browser => store home
So, if this suits your needs then everything should be fine. If you want to include the redirect page in the browser history replace this
if( url ) window.location.replace(url);
with
if( url ) window.location.href = url;
You need to put this line in your code:
$(location).attr("href","http://stackoverflow.com");
If you don't have jQuery, go with JavaScript:
window.location.replace("http://stackoverflow.com");
window.location.href("http://stackoverflow.com");
On your click function, just add:
window.location.href = "The URL where you want to redirect";
$('#id').click(function(){
window.location.href = "http://www.google.com";
});
Try this:
location.assign("http://www.google.com");
Code snippet of example.
jQuery is not needed. You can do this:
window.open("URL","_self","","")
It is that easy!
The best way to initiate an HTTP request is with document.loacation.href.replace('URL').
Using JavaScript:
Method 1:
window.location.href="http://google.com";
Method 2:
window.location.replace("http://google.com");
Using jQuery:
Method 1: $(location)
$(location).attr('href', 'http://google.com');
Method 2: Reusable Function
jQuery.fn.redirectTo = function(url){
window.location.href = url;
}
jQuery(window).redirectTo("http://google.com");
First write properly. You want to navigate within an application for another link from your application for another link. Here is the code:
window.location.href = "http://www.google.com";
And if you want to navigate pages within your application then I also have code, if you want.
You can redirect in jQuery like this:
$(location).attr('href', 'http://yourPage.com/');
JavaScript is very extensive. If you want to jump to another page you have three options.
window.location.href='otherpage.com';
window.location.assign('otherpage.com');
//and...
window.location.replace('otherpage.com');
As you want to move to another page, you can use any from these if this is your requirement.
However all three options are limited to different situations. Chose wisely according to your requirement.
If you are interested in more knowledge about the concept, you can go through further.
window.location.href; // Returns the href (URL) of the current page
window.location.hostname; // Returns the domain name of the web host
window.location.pathname; // Returns the path and filename of the current page
window.location.protocol; // Returns the web protocol used (http: or https:)
window.location.assign; // Loads a new document
window.location.replace; // RReplace the current location with new one.
In JavaScript and jQuery we can use the following code to redirect the one page to another page:
window.location.href="http://google.com";
window.location.replace("page1.html");
ECMAScript 6 + jQuery, 85 bytes
$({jQueryCode:(url)=>location.replace(url)}).attr("jQueryCode")("http://example.com")
Please don't kill me, this is a joke. It's a joke. This is a joke.
This did "provide an answer to the question", in the sense that it asked for a solution "using jQuery" which in this case entails forcing it into the equation somehow.
Ferrybig apparently needs the joke explained (still joking, I'm sure there are limited options on the review form), so without further ado:
Other answers are using jQuery's attr() on the location or window objects unnecessarily.
This answer also abuses it, but in a more ridiculous way. Instead of using it to set the location, this uses attr() to retrieve a function that sets the location.
The function is named jQueryCode even though there's nothing jQuery about it, and calling a function somethingCode is just horrible, especially when the something is not even a language.
The "85 bytes" is a reference to Code Golf. Golfing is obviously not something you should do outside of code golf, and furthermore this answer is clearly not actually golfed.
Basically, cringe.
Javascript:
window.location.href='www.your_url.com';
window.top.location.href='www.your_url.com';
window.location.replace('www.your_url.com');
Jquery:
var url='www.your_url.com';
$(location).attr('href',url);
$(location).prop('href',url);//instead of location you can use window
Here is a time-delay redirection. You can set the delay time to whatever you want:
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Your Document Title</title>
<script type="text/javascript">
function delayer(delay) {
onLoad = setTimeout('window.location.href = "http://www.google.com/"', delay);
}
</script>
</head>
<body>
<script>
delayer(8000)
</script>
<div>You will be redirected in 8 seconds!</div>
</body>
</html>

GWT: How to make sure a javascript is run after the GWT page is constructed

I have a javascript file main.js. The main.js contains something like this:
$(document).ready(function() {
Cufon.replace('#myform p.head', { fontFamily: 'HelveticaNeueLT Std Thin' });
......
});
I suppose what this does is to run this method after the whole page is loaded and apply the change to the css elements.
But what I found out is that this only works when the script is loaded before all the HTML elements, e.g.:
<body>
HTML......
<script type="text/javascript" src="js/main.js"></script>
</body>
However, if this script is put on top of all the HTML, it stops working:
<body>
<script type="text/javascript" src="js/main.js"></script>
HTML......
</body>
This happens on both static HTML and the GWT page. Because my GWT always put the generated HTML stuff at the end of all the body contents, the script is always before the HTML, hence is does not work. For example, my HTML for GWT module is like this:
<body>
<script type="text/javascript" src="js/main.js"></script>
</body>
And after compiled, the generated HTML from my UIBinding gives HTML page like:
<body>
<script type="text/javascript" src="js/main.js"></script>
Generated HTML....
</body>
My questions are:
Is there anyway in GWT where I can specify the generated HTML goes
between some statements in the tag.
Is there any other ways instead of $(document).ready I can guarantee
it is called as the last thing happened in a page load?
Many thanks
While I find it strange that the script doesn't work as intended when moved up in a static page ($(document).ready(…) is supposed to wait for the </html> to be reached –aka DOMContentLoaded– before running the function passed to it), it's not the reason it doesn't work with your GWT application (in other words, your diagnostic is wrong).
GWT's onModuleLoad also runs at DOMContentLoaded (or later, but never earlier) so you probably have a race condition between your app's onModuleLoad and jQuery's $(document).ready(…). You could try putting the <script> for your GWT app before the main.js, but because onModuleLoad might run after DOMContentLoader anyway, there's no guarantee it'll work (even less in a crossbrowser way).
I think you'd better remove the main.js or replace the $(document).ready(…) with a simple function, and call Cufon (and/or whatever else you were doing in $(document).ready(…)) from within your GWT app, at the moment appropriate for your needs (i.e. after you attached the #myform p.head element/widget to the document).
The easiest way to do that is to put the script in a JSNI method and then call that method where appropriate. Just make sure you use $wnd.Cufon instead of Cufon (and similarly for all other globals), and replace all occurrences of document with $doc and window with $wnd.
public static void cufon() /*-{
$wnd.Cufon.replace('#myform p.head', { fontFamily: 'HelveticaNeueLT Std Thin' });
}-*/;

Displaying Loading gif or waiting message until servlet loads

I have a application that invokes a servlet through the URL
> "http://server:port/context-root/myservlet"
The servlet then calls the Java Class which returns the query result back to servlet.The servlet then renders the data to the user through a JSP page(response.redirect)
Now it hapens so, when all this happens Page Cannot be displayed is rendered to the useruntil the JSP page is ready to show the data.
How can I show a loading gif or a messgae as soon as the servlet is invoked until the JSP page is loaded with all the required data:
NOTE: As mentioned above, I am first calling the servlet, then Java Class, then JSP.
#Sankalp - The invoking application (HTML page ) is solely responsible for making an AJAX Call to your servlet. If you dont have control over the invoking application here is a little trick you can do - Ask the invoking application to re-direct to an html file say an index.html file of your application . In the index.html file , export jQuery javascript library and make appropriate ajax call , show a loading image , and upon success you may re-direct the page to desired jsp. There is a lot of work to be done here.
Question : Does the invoking application pass you any parameters ?
Does it POST data to you ?
Does your application open in an IFRAME of the invoking application or its a pure re-direct ?
All these answers , would help you decide your next course of action. There are lots of post on AJAX calls and showing images on stack overflow but that does not solve your essential problem . You have to decide on the flow and where to put the AJAX code. The AJAX part would be the easiest one. :)
----- Editing after the last comment
Visit : jQuery
In your HTML
<html>
<head>
<script src="jquery.min.js"></script> <!-- where you keep your resource file -->
<script language="javascript" type="text/javascript">
$(document).ready(function() { //This call will be made when DOM
//hierarchy has been fully constructed
// Handler for .ready() called.
//Make AJAX Call here so that this simple HTML page
///directly calls the AJAX
// and decide the future action based on AJAX success / failure
});
</script>
</head>
<body>
</body>
</html>

Getting Started With GWT

I have been looking into the GWT for a couple of days now and I have some confusion.
I come from a PHP/JSP background so when I wanted to create a website that had multiple pages I would just create a PHP page for each page and then let the user select what to view.
Now that I am looking into GWT I don't really understand how this is done?
Lets say I would like my site to have three pages (index.html, help.html, contact.html), when a GWT app is loaded the onModuleLoad() method is called. How would I then code each separate pages widgets then using only this one method?
Looking at the example GWT application that is created in Eclipse, A single HTML page is created. How would I create an application with multiple pages if there is only a single onModuleLoad() method?
GWT can be used in a Web 2.0, client-side application way as mentioned by Chris Lercher and nvcleemp or you can use it in conjunction with a more traditional page view/reload model. If you simply want to inject DHTML functionality into existing, static pages, you can look for specific element id's for injecting into or you could read a javascript embedded configuration variable when onModuleLoad() is called to determine what state/mode you are in and what type of GWT client functionality you should be running.
For example, using the different injection points:
page 1:
<html>
<head>
...
<script type="text/javascript" src="yourmodule.nocache.js"></script>
...
</head>
<body>
...
<div id="injectMode1"></div>
...
</body>
</html>
page 2:
<html>
<head>
...
<script type="text/javascript" src="yourmodule.nocache.js"></script>
...
</head>
<body>
...
<div id="injectMode2"></div>
...
</body>
</html>
Your GWT EntryPoint:
#Override
public void onModuleLoad() {
final Panel mode1 = RootPanel.get("injectionMode1");
if (mode1 != null) {
mode1.add(new ModeOneWidget());
}
final Panel mode2 = RootPanel.get("injectionMode2");
if (mode2 != null) {
mode2.add(new ModeTwoWidget());
}
}
EDIT:
Using javascript variables, on each page that you want to embed GWT functionality you can do something similar to:
page foo:
<html>
<head>
...
<script type='text/javascript'>
var appMode="mode1";
</script>
<script type="text/javascript" src="yourmodule.nocache.js"></script>
...
</head>
...
Your GWT EntryPoint:
private static final native String getAppMode()/*-{
return $wnd.appMode;
}-*/;
#Override
public void onModuleLoad() {
String appMode = getAppMode();
if(appMode != null){
if(appMode.equals(MODE1)){
...
}
...
}
}
GWT uses JavaScript to modify the page content. So you don't load a new page [*].
With GWT, you don't need the server to create dynamic HTML content anymore. It's created dynamically on the client side (using static JavaScript code). When you need to load something from the server, you just load data objects (in JSON or XML format, or using GWT-RPC). The client may then use this data to build HTML snippets (to set innerHTML) or DOM objects to modify the browser's DOM tree.
With GWT, you don't have to build these snippets manually: You can use Widgets and UiBinder (client side HTML templating, enhanced with GWT tags and dynamic parameters).
[*] There are some special cases (e.g. if you have a https login page, whereas the rest of the app might use http), where you do load a new page, but that means either that your other page doesn't use GWT at all, or that you create a separate GWT module for it. Of course you can share some of the Java classes between these modules.
GWT is used to build applications like e.g. Google Reader or Gmail: this means that there is just 'one' page. You could have a 'window' inside that page that shows the contact information and a 'window' that shows the help information. When the users clicks the corresponding link you show that 'window'

google.load issue

Hi I am messing around with google ajax api at the momemt and following the examples from the documentation I have two script tags in my html file:
<script src="http://www.google.com/jsapi" type="text/javascript"></script>
<script language="Javascript" type="text/javascript">google.load('search', '1');</script>
All works fine, but it will not work when I am using jquery and trying to call the google.load('search', '1'); in an external javascript file after $(document).ready(function()
I get the following error: null is null or not an object.
I am obviously missing something fundamental as I am just learning javascript but I was under the impression that it is best to use javascript unobtrusively. The second script tag that actually contains some js code isnt unobtrusive. Can anyone lend any help with this please?
From what you have explained it seems your page is setup something like this:
<script src="http://www.google.com/jsapi" type="text/javascript"></script>
<script type="text/javascript">
google.load('jquery');
$(document).ready(function(){
... do stuff ...
});
</script>
<script src="/my/external.js" type="text/javascript"></script>
However, this will not work as you expect since the document.ready event will not fire until the DOM is completely loaded. JavaScript files, however, are executed as they are loaded. So the actual execution looks like this:
Load Google JSAPI
Load jQuery
Load External.js
Call Document Ready
Depending on what the rest of your code looks like, you might want to either put all your initialization code in a separate file, or move your search load back into the main document.
ABOUT UNOBTRUSIVE CODE:
David, unobtrusive JavaScript has to do with how it affects the page, not with whether or not it is in-page or external.
It is more about not making your site so dependent on JavaScript that it does not function with it disabled
For instance, this is obtrusive:
Click Me
Because it will only work with JavaScript enabled. Additionally the code is inline which is bad because it does not separate functionality from structure (HTML).
However, taking a similar piece of code:
Click Me
and using this javascript/jquery snippet:
$(document).ready(function(){
$("#do-something").click(function(e){
doSomethingNicer();
e.preventDefault(); // Keep the browser from following the href
});
});
Is becomes unobtrusive because the page still works (loads /do/something by default), but it works in a nicer way when JavaScript is enabled (executes the javascript instead of loading that url). This is also called Progressive Enhancement.

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