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pass parameter to $.selector for ajax GET request call

i have pagination links echoed with a for loop like this '<< < > >>".
echo "<a href='{$_SERVER['PHP_SELF']}?currentpage=$prevpage'>< </a>"
somewhere within my codes i set the $currentpage using GET request:
if (isset($_GET['currentpage']) && is_numeric($_GET['currentpage'])){
$currentpage = (int)$_GET['currentpage'];
}else{
$currentpage = 1;
}
//the offset of the list , based on current page
$offset = ($currentpage-1) * $rowsperpage;
and i have a session variable to hold search criteria selected by the user while he navigates the page links. The logical error i get is when user clicks any of the pagination link, the session variable wipes out and table displays without the search criteria.
After intensive research i figured out i can use ajax but am confused on how to arrive my goals. THis is what i tried doing. please some help will do.
$('#pglink).click(function(e,$prevpage){//***i need to pass the current page parameter for clicked link
e.preventDefault();
var pgNo = $prevpage;
$.ajax({
url:"file.php",
type: "get",
data:{
currentpage: pgNo }
});
});

how to get data from server without refreshing the page

I am new to web development. My job is to get data from the server and plot them using amcharts every 1 or 2 seconds.
This is what i have so far:
<form id="getdata" role="form" method="post" action=#routes.DataApplication.get_data()>
<input type="text" name="device" id="device">
<input type="text" name="type" id="type">
<button id = "submit" type="submit">Submit</button>
</form>
Once I enter device and type and click the submit button, it will run the Java method get_data(). The method will search the database and return data that matches the device name, but the thing is it will display is the data in another page, for example www.somepage/getdata. The above html is in www.somepage/data page.
I tried using jquery .post() but the thing is it requires an url, I tried passing /getdata to it but didn't work.
My question is: is there a way to save the data we get from the #routes.DataApplication.get_data() action without reloading the page?
By the way, I am using play framework to develop the webpage.
UPDATE
Ok, making some progresses now, I tried using ajax post, but the data return (in console) is like this:
[Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object]
Here I got 11 objects. If i don't use ajax post (using the original post form method), I get 11 data points too.
Here is my code:
<script>
$('#driver').click(function(evt) {
var dataabc = $('form').serialize();
console.log(dataabc);
$('#errors').hide();
$.ajax({
type : 'POST',
data : dataabc,
url : '#routes.DataApplication.get_data()',
success : function(data) {
alert("good");
console.log(data);
},
error : function(result) {
setError('Make call failed');
}
});
return false;
});
</script>
What get_data() does is just take the user input data (which is the form) and get corresponding data from the database and return ok(node);. This node is JsonNode
Any help would be appreciated..

Since you are getting an array of objects back in javascript and it is stored in data. You can loop through it and display the content is some div tag.
Example:
Create an empty div to populate the data after a successful ajax call.
<div id="mytextarea"></div>
Then in your ajax success, instead of printing to console you would loop through the array and append the data to the innerHTML of the div tag like so...
var myTextArea = document.getElementById('mytextarea');
for (var x = 0; x < data.length; x++){
myTextArea.innerHTML = myTextArea.innerHTML + data[x].id + '<br/>';
}
Edit 1: I see you know your object's attributes so I updated the code to append just id to the text area.

It will be very helpful to tell us what exactly the url returns in response. Usually that should be XML or JSON.
You can use FireBug or any other developer tools to catch the response and post it here.

IT doesn't decide what to return - it's YOU!
If you'll return for an instance JSON object in your get_data() action, your AJAX will receive a JSON, check yourself:
public static Result get_data(){
ObjectNode node = Json.newObject();
node.put("hello", "world");
return ok(node);
}

access javascript variable value in jsp

I want to pass a javascript variable to my servlet, where I need to use it.
In javascript, the variable count returns the rows of my table and I can show count in the jsp, using $('#counter').html(count); , but I cannot pass count's value to my servlet. I tried document.getElementById("hiddenField").value=count; but it doesn't work.
Javascript
<script>
var count = 3;
$(function() {
$('#counter').html(count);
$('#addButton').bind('click', function() {
count = document.getElementById("dataTable").getElementsByTagName("tr").length;
$('#counter').html(count);
});
$('#deleteButton').bind('click', function() {
count = document.getElementById("dataTable").getElementsByTagName("tr").length;
$('#counter').html(count);
});
});
document.getElementById("hiddenField").value=count; // ???
</script>
JSP
Count: <span id="counter"></span> <%-- it works --%>
<form method="post" action="newteamsubmit">
...
<input type="hidden" id="hiddenField" name ="countRows" />
<input type="submit" name ="button1" value=" Submit " />
<input type="submit" name = "button1" value=" Cancel " />
</form>
Servlet
String cr = request.getParameter("countRows"); //I' ve tried also to convert it
// to int, but that's not my problem, since I cannot pass the value as a start
I've spent many hours, trying to figure out how I can access a javascript variable in jsp, but I haven't found any solution.
Thanks in advance.

The count is computed each time the add button or the delete button are clicked. But you only set the hidden field value once, when the page is loaded (and its value is thus hard-coded to 3).
You must set it, as you're doing for the #counter element, in your click handlers:
$('#addButton').bind('click', function() {
count = document.getElementById("dataTable").getElementsByTagName("tr").length;
$('#counter').html(count);
$('#hiddenField').val(count);
});
$('#deleteButton').bind('click', function() {
count = document.getElementById("dataTable").getElementsByTagName("tr").length;
$('#counter').html(count);
$('#hiddenField').val(count);
});
Also note that you're repeating exactly the same code in two click handlers here. You should do that only once, for the two buttons:
$('#addButton, #deleteButton').bind('click', function() {
count = document.getElementById("dataTable").getElementsByTagName("tr").length;
$('#counter').html(count);
$('#hiddenField').val(count);
});
or even, since you're using jQuery:
$('#addButton, #deleteButton').bind('click', function() {
count = $("#dataTable tr").length;
$('#counter').html(count);
$('#hiddenField').val(count);
});

document.getElementById('hiddenField').value is not set because it is outside your document.ready. Put it inside your click handler.

Make sure of 2 things -
There is only one element with id "hiddenField" on your page.
Make sure that the following code
document.getElementById("hiddenField").value=count;
is after in the page.
Just make sure that js sets the hiddenField after the element has been loaded.
3. check for any JS errors using Javascript console.
Rest it looks good

The main issue here is that you are trying to access from the server, a variable that only exists at the client. To access that variable you have to send it from the client to the server using AJAX to trigger some form of API in the backend. REST, SOAP or XML-RPC are common technologies used for this sort of thing. The server side code is used for generating the UI and providing it with data from a database or such. Commonly the UI is generated only once, and then the client calls the server asking for more data in response to user actions, like clicking a button.
Imagine a table filled with information about books: title, author, publish date etc. This table can get quite large, and traditionally this table will be split up over several pages and possibly a dynamic filter. To save bandwidth and increase the user experience by not loading the entire page from scratch you can use AJAX to ask the server for just the relevant data. Doing so the page updates dynamically and smoothly for the user.
In your case, you can use this technique to update the server every time the user clicks the button.
If however you are really just looking to update a hidden field in a form with a value as the user performs actions, and the server wont do anything with it except show it you can just use javascript.
Remember also that the request variable contains the data you post to the server when you submit the form. The servlet will get the data after the client has posted it, which is after the JSP has generated the page. The sequence of the code execution is JSP -> Javascript -> Servlet.
Hope this helps!

You can use this way:
document.forms[0].countRows.value = counter
Hope this will help you

Populate form field with variable set in javascript

I have a form in my play framework project. The user inputs a series of values. I need to store another value in my model as well but I don't want it to be displayed, it has to be hidden. The other complication is that I want this hidden value to store the value of a variable that is determined after the form has been submitted (because it uses one of the values entered by the user to get the variable). Is there a way to do this or would I have to create a separate model to handle this?

I don't want it to be displayed, it has to be hidden.
Option 1: either bind the value to the element using $.data() if you use jQuery which is the cleanest approach to do this
Option 2: Put this value as text in a <input type='hidden' disabled='disabled'>. Not recommended
The other complication is that I want this hidden value to store the value of a variable that is determined after the form has been submitted
Update the value on the success handler of ajax request
$.ajax({
url: '#wherever',
data: $('#yourform').serialize();
success: function(e) { // update the original value from response here },
error: function(e) { // something bad occured, handle it!! }
});

dynamically update textbox value from database when combobox value is changed

Here is the situation. I have a drop down menu. The option sin this drop down menu are being populated by fetching some values from the database. To do this following is what i have done.. :-
<select name="product_list" onchange="selectProduct(this.value)">
<option value="none">Select one</option>
<%
List<String> options = new ArrayList<String>();
DynamicCombo comboBox = new DynamicCombo();
options = comboBox.generateComboBox();
Collections.sort(options);
int tempVar = 0;
while (tempVar < options.size()) {
out.print("<option value=\"");
out.print(options.get(tempVar));
out.print("\">");
out.print(options.get(tempVar));
out.print("</option>");
tempVar++;
}
%>
</select>
DynamicCombo is a class that has a method called 'generateComboBox()'. This method simply returns an array list containing all the values that are fetched from the database, which is what i need to show in my drop down box in the front end (jsp page). On my jsp page i simply iterate through this list and print it as options appropriately.
This works absolutely fine.
Now i have another text box on my form, say 'textbox1'. Now the requirement is that this text box value should be updated depending on what the user has selected from the above drop down box.
So for example if the user selects 'prod1'(which is a primary key in the backend database table) option from the drop down box, then the corresponding value ( the product name) should be fetched from the database table and should be updated in the textbox named 'textbox1'.
The other thing is this entire thing is contained in a form which is supposed to be finally submitted to the servlet for further processing.
So how can i achieve this.

i figured out the solution to my own problem. It might not be the most elegant way of doing it, but it does the job pretty well.
So as per my requirement, what i exactly wanted to do was.... insert a value (that will be fetched from the database) into a text box on my form depending on what the user chooses from the drop down box that is already present on my form.
To achieve this, i went about and thought if some how i could nest a form withing my main form, it'd solve my issue. But i discovered that nesting of forms is not allowed. So the next option i thought of was to some how submit the same form without the user clicking on the submit button and also handle it appropriately as an 'incomplete' submit (in the sense that the form is still to be submitted manually by the user by clicking on the submit button) on the server.
So i simply made use of the 'onChange' event of a drop down box. I created an additional hidden field on my form.I wrote a simple javascript function that would simply set the value of the hidden field to the string-"partial Submit" and would submit my main form (say named 'form1') as :-
document.getElementById("hidden_id").setAttribute("value","partial submit");
form1.submit;
The function that does the above will be called whenever (and everytime) the onchange event of the drop down box gets fired.
When the user finally clicks on the submit button on the form to submit the finally completed form, then another javascript function is called that simply sets the value of the hidden field on the form to the string, "final submit" and would submit the form as :-
document.getElementById("hidden_id").setAttribute("value","final submit");
form1.submit;
Now on my server, i checked for the value of this hidden field as :-
if(request.getParameter("hidden_id").equals("partial Submit"))
{
// make a database connection, pass the value user selected from the drop down box
// to a prepared statement that does the query for getting the 'productName' from
// the database, collect the returned string in a variable and set a
// request attribute with this returned value. This value can simply be used in the
// jsp to fill in the value part of the textbox1.
}
else
{
if(request.getParameter("hidden_id").equals("final Submit"))
{
// do the rest of the final processing that needs to be done when user finally
// submits the completed form.
}
else
{
// throw an exception to take care of the possibility that the user might send
// in a 3rd value as a value for the hidden field.
}
}

Since you havent provided the code for selectProduct(this.value) , i presume that it submits the jsp page as when you change the value in the drop down.
If that the case in the servelt, set the value that you want to show in jsp in request object
request.setAttribute("valuetodisplay" ,valuetodisplay);
and now in jsp
<input type="text" value ='<%= request.getAttribute("valuetodisplay")%>' />