I need to test the browser window width in JSP, to determine whether or not I have to set a value in the request object. Typically I would achieve this with something like this:
if(document.body.offsetWidth < xxxx){
// ...
}
But I don't know how to do it with a JSP expression.
You might misunderstand that jsp and javascript existed on same file. Yes but JSP part compiles on server side itself comes to client.
You can't do that with JSP.
JSP compiles on serverside Where as javascript plays on browser i.e on client side.
Do it with javascript.You should do it in document load
when you do if(document.body.offsetWidth < xxxx) you are doing it at client side. Now if you want to propagate some client side value to server side i.e to some java class(most of the cases it will be servlets) then you have two options:-
1)Make an AJAX call. (You can also use jquery here to make AJAX call).
Here is the small example, you can find ample on google
$.ajax({
type: 'GET',
dataType: 'json',
data: { windowWidth: "100"}
url: servlerURL,
success: function(reply) {
},
error: function (xhr, textStatus, errorThrown) {
}
});
or
2)Submit the form
Related
While click on an add button i have given the jquery code to navigate next page.
Here is my jQuery code:
$("#id-add-mer").click(function(){
location.href="../ecom/addMer";
});
here is my controller:
#RequestMapping(value = "/addMer", method = RequestMethod.GET)
public String addMerchant() {
return "merchantRegistration";
}
here it redirects to that page, but i have 3 dynamically fetching dropdown inside this page. i'm trying to fetch the values by adding an onload event in the body tag. here is my ajax code
function loadDropDown(){
$.ajax({
type: 'POST',
url: "ecom/loadInd",
data: {},
dataType: "json",
success: function(data) {
count = Object.keys(data).length;
$("#id-industry").empty();
for(i=0;i<count;i++){
$("#id-industry").append('<option value="'+data[i].id+'">'+data[i].type+'</option>');
}
loadBank();
},
error: function(jqXHR, textStatus, errorThrown) {
alert("1Server Exception");
}
});
}
i'm making an ajax call to fetch 2nd dropdown at the success of 1st call. while loading this page as welcome file displays the fetched dropdowns, i'm using spring mvc and hibernate to retrieve the records. But here i'm getting the error. Can anyone tell me how can i fix this issue..Thanks in advance...
Its better if you can mention here, what you get as error message in your code. Otherwise try to follow below steps to identify the issue.
First of all you better check whether your http request can access your server. you can use third party tools as well as built-in element viewer for that.
if there is no issue with communication with controller then check the what will return from "/loadInd". Simply you can debug or you can use alert box to inside success block.
Happy Coding....
I am using Jquery Ajax calls to access REStful webservices as below. The webservice is hosted on different domain.
$.ajax({
type: "GET",
url: "some url hosted on differnt domain",
crossDomain: true,
contentType: "application/json; charset=utf-8",
dataType: "jsonp",
success: function(responseJson) {
alert("json"+responseJson);
},
error: function(xhr, status, error) {
var err = eval("(" + xhr.responseText + ")");
alert(err.Message);
}
});
Am not sure whether it is not hitting the webservice.It is going to error block but no alert is displayed. Am i doing anything wrong here?
Thanks!
You got to change the Header at you server side http://www.w3.org/TR/cors/#access-control-allow-origin-response-header
Since it will cause forgery. For more of cors understanding http://enable-cors.org/server.html
You can't make cross domain request just like that. It might cause cross-site forgery. Check this-
http://en.wikipedia.org/wiki/Cross-site_request_forgery
Basically, to be able to do so, the server should allow you to do that. If you access some resource on a cross domain server. The server responds back with a list of allowed users for that resource. The browser reads that list. If you are not listed in that list then the browser won't show the resource to you.
Solutions:
1- You should have control of the server side.
2-you can try 'script' tags in HTML for your purpose. They are an exception to this. You can make cross-domain requests using 'script' tags and then parse the response as json.
3-Jsonp callbacks.
I haven't actually implemented in much detail because I have control over server side whenever I need. And, CDNs are open to all. So, you might want to do some reading now to figure out more.
I am getting errors on callBacks. I have tried following code in jsfiddle.com . You can also try. Data from servelet is not returning. It's returning same error again and again. Check jquery library when you try in jsfiddle
$.ajax({
url : 'http://192.168.16.111:8081/MiddleWareUsman/androidServlet',
type : "post",
dataType: "jsonp",
data : {
"fname": "chaaaaapiio",
"lname": "gya"
},
success : function(data) {
alert("hello"+data);
},
error : function(xhr, ajaxOptions, thrownError) {
alert(thrownError);
}
});
My server side:
String a=request.getParameter("fname");
String b=request.getParameter("lname");
response.getWriter().write(a+" "+ b);
It appears you have a couple problems.
JSONP requests can't be sent via POST. They are actually sent as <script> tag requests anyway which are GET requests.
Your server isn't doing JSONP. For the server to do JSONP, it must wrap the requested data in a call to a javascript function who's name was passed as an argument to the request and then the actual data is passed as an argument to that function. JSONP is a big hack, but it works by requesting a javascript and that's what the server must return.
you simply can't send a POST request using JSONP
check this link out to see how JSONP works..
I wrote a server program in java but in order to give an interface with web i want to access java method in jsp when certain menu button is clicked. How can i do this?
Using ajax (using jQuery.ajax, you could make a request to server, In your case may be to a Servlet which will invoke method on server that you requested
For example:
function callMe(){
$.ajax({
type: "POST",
url: "/someServlet",
data: { methodToInvoke: "sayHello" , data: "Abc" }
}).done(function( msg ) {
alert( "Data Saved: " + msg );
});
}
at Servlet end
doPost(...){
String methodToCall = request.getParameter("methodToCall");
//do some stuff to determine method to call and call it like
methodService.invoke(request.getParameter("data"));
}
Also See
DWR
you cannot do this directly because JSP is server side and html is client side. However, it can be accomplished via AJAX. http://en.wikipedia.org/wiki/Ajax_(programming)
I'm porting working PHP application to Java/Wicket.
I have a lot of complex, well written jQuery/javaScript which I would like to reuse and not change too much.
Obviously I have to change urls in ajax calls and rewrite the server side scripts from PHP to Java.
I tought this task would be simple but somehow I can't figure out how to write server side that would respond to ajax call.
Simple example:
javascript:
function f(){
jQuery.ajax({
data: 'object_type=1&object_id=2',
url: 'ajax/get_object.php',
timeout: 2000,
type: 'POST',
dataType: 'json',
success: function(r) {
alert(r);
}
});
}
Php file ajax/get_object.php:
// ... create $json_string here
echo $json_string;
I have found AbstractDefaultAjaxBehavior which I probably should use to implement server side of such ajax call, but I'm not really sure how to use it.
I'm not really Java kind of guy so try to explain step by step what sould I do :-)
Have a look at This Ajax Wicket tutorial and search for AjaxEventBehavior.
Do note that Wicket assumes that browsers lacking javascript (Braille readers for the disabled for instance) can return full pages (full page reload in stead of AJAX). If you're doing a job for the government that's usually also a requirement.