According to the [w3 spec section 4.6.3 for XMLHttpRequest][1] a user agent should honor the Set-Cookie header. So the answer is yes you should be able to.

Quotation:

&gt; If the user agent supports HTTP State Management it should persist,
&gt; discard and send cookies (as received in the Set-Cookie response
&gt; header, and sent in the Cookie header) as applicable.


  [1]: http://www.w3.org/TR/XMLHttpRequest

**Yes**, you can set cookie in the AJAX request in the server-side code just as you&#39;d do for a normal request since the server cannot differentiate between a normal request or an AJAX request.

AJAX requests are just a special way of requesting to server, the server will need to respond back as in any HTTP request. In the response of the request you can add cookies.

For the record, be advised that all of the above is (still) true only if the AJAX call is made on the same domain. If you&#39;re looking into setting cookies on another domain using AJAX, you&#39;re opening a totally different [can of worms][1]. Reading cross-domain cookies does work, however (or at least the server serves them; whether your client&#39;s UA allows your code to access them is, again, a different topic; as of 2014 they do).

  [1]: https://developer.mozilla.org/en-US/docs/HTTP/Access_control_CORS?redirectlocale=en-US&amp;redirectslug=HTTP_access_control#Requests_with_credentials

Also check that your server isn&#39;t setting secure cookies on a non http request.  Just found out that my ajax request was getting a php session with &quot;secure&quot; set.  Because I was not on https it was not sending back the session cookie and my session was getting reset on each ajax request.

In Java, How do I get the current index for the element in Java?

    for (Element song: question){
        song.currentIndex();         //&lt;&lt;want the current index.
    }

In PHP you could do this:

    foreach ($arr as $index =&gt; $value) {
        echo &quot;Key: $index; Value: $value&quot;;
    }



Java, How do I get current index/key in &quot;for each&quot; loop

Is it possible to declare two variables of different types in the initialization body of a for loop in C++?

For example:

    for(int i=0,j=0 ...

defines two integers. Can I define an `int` and a `char` in the initialization body? How would this be done?

Is it possible to declare two variables of different types in a for loop?

Can an AJAX response set a cookie?  If not, what is my alternative solution?  Should I set it with Javascript or something similar?


Can an AJAX response set a cookie?

<p>Can an AJAX response set a cookie?  If not, what is my alternative solution?  Should I set it with Javascript or something similar?</p>


I want an HTML form to do nothing after it has been submitted.

    action=&quot;&quot;

is no good because it causes the page to reload.

Basically, I want an Ajax function to be called whenever a button is pressed or someone hits &lt;kbd&gt;Enter&lt;/kbd&gt; after typing the data. Yes, I could drop the form tag and add just call the function from the button&#39;s onclick event, but I also want the &quot;hitting enter&quot; functionality without getting all hackish.




Want HTML form submit to do nothing

I have a jquery-based single-page webapp. It communicates with a RESTful web service via AJAX calls. 

I&#39;m trying to accomplish the following:

1. Submit a POST that contains JSON data to a REST url.
2. If the request specifies a JSON response, then JSON is returned.
3. If the request specifies a PDF/XLS/etc response, then a downloadable binary is returned.

I have 1 &amp; 2 working now, and the client jquery app displays the returned data in the web page by creating DOM elements based on the JSON data. I also have #3 working from the web-service point of view, meaning it will create and return a binary file if given the correct JSON parameters. But I&#39;m unsure the best way to deal with #3 in the client javascript code.

Is it possible to get a downloadable file back from an ajax call like this? How do I get the browser to download and save the file?

    $.ajax({
    	type: &quot;POST&quot;,
    	url: &quot;/services/test&quot;,
    	contentType: &quot;application/json&quot;,
    	data: JSON.stringify({category: 42, sort: 3, type: &quot;pdf&quot;}),
    	dataType: &quot;json&quot;,
    	success: function(json, status){
    		if (status != &quot;success&quot;) {
    			log(&quot;Error loading data&quot;);
    			return;
    		}
    		log(&quot;Data loaded!&quot;);
    	},
    	error: function(result, status, err) {
    		log(&quot;Error loading data&quot;);
    		return;
    	}
    });

The server responds with the following headers:

    Content-Disposition:attachment; filename=export-1282022272283.pdf
    Content-Length:5120
    Content-Type:application/pdf
    Server:Jetty(6.1.11)

Another idea is to generate the PDF and store it on the server and return JSON that includes a URL to the file. Then, issue another call in the ajax success handler to do something like the following:

    success: function(json,status) {
        window.location.href = json.url;
    }

But doing that means I would need to make more than one call to the server, and my server would need to build downloadable files, store them somewhere, then periodically clean up that storage area.

There must be a simpler way to accomplish this. Ideas?

---
EDIT: After reviewing the docs for $.ajax, I see that the response dataType can only be one of `xml, html, script, json, jsonp, text`, so I&#39;m guessing there is no way to directly download a file using an ajax request, unless I embed the binary file in using Data URI scheme as suggested in the @VinayC answer (which is not something I want to do).

So I guess my options are:

1. Not use ajax and instead submit a form post and embed my JSON data into the form values. Would probably need to mess with hidden iframes and such.

2. Not use ajax and instead convert my JSON data into a query string to build a standard GET request and set window.location.href to this URL. May need to use event.preventDefault() in my click handler to keep browser from changing from the application URL.

3. Use my other idea above, but enhanced with suggestions from the @naikus answer. Submit AJAX request with some parameter that lets web-service know this is being called via an ajax call. If the web service is called from an ajax call, simply return JSON with a URL to the generated resource. If the resource is called directly, then return the actual binary file.

The more I think about it, the more I like the last option. This way I can get information back about the request (time to generate, size of file, error messages, etc.) and I can act on that information before starting the download. The downside is extra file management on the server.

Any other ways to accomplish this? Any pros/cons to these methods I should be aware of?
 



JavaScript/jQuery to download file via POST with JSON data

Here are two pages, test.php and testserver.php.

**test.php**

    &lt;script src=&quot;scripts/jq.js&quot; type=&quot;text/javascript&quot;&gt;&lt;/script&gt;
    &lt;script&gt;
        $(function() {
            $.ajax({url:&quot;testserver.php&quot;,
                success:function() {
                    alert(&quot;Success&quot;);
                },
                error:function() {
                    alert(&quot;Error&quot;);
                },
                dataType:&quot;json&quot;,
                type:&quot;get&quot;
            }
        )})
    &lt;/script&gt;

**testserver.php**

    &lt;?php
    $arr = array(&quot;element1&quot;,
                 &quot;element2&quot;,
                 array(&quot;element31&quot;,&quot;element32&quot;));
    $arr[&#39;name&#39;] = &quot;response&quot;;
    echo json_encode($arr);
    ?&gt;

Now my problem: when both of these files are on the same server (either localhost or web server), it works and `alert(&quot;Success&quot;)` is called; If it is on different servers, meaning testserver.php on web server and test.php on localhost, its not working, and `alert(&quot;Error&quot;)` is executing. Even if the URL inside ajax is changed to http://domain.com/path/to/file/testserver.php


jQuery AJAX cross domain

I&#39;m utilizing the magic of `jQuery.ajax( settings )`.

However, I&#39;m wondering if anyone has played with the timeout setting much?

I know it&#39;s basically for dictating the local time for a request, but can it trigger anything if the timeout is reached?  Or does it simply stop listening for a response?

Reading the jQuery site, I can see there are no arguments passed, so it seems like a simple setting with one capability.  Which is fine.  

But, I&#39;d like to trigger an alert or some function if the timeout is reached. I can see that the error setting doesn&#39;t get triggered, in this case.

Here&#39;s my snippet:
 

    $(&quot;form#testform&quot;).submit(function(){ 
       
     var allFormValues = $(&quot;form#testform&quot;).serialize(); 
     
       $.ajax({
        cache:false,
        timeout:8000,  // I chose 8 secs for kicks
        type:&quot;POST&quot;,
        url:&quot;someurl.php&quot;,
        data:allFormValues,
        error:function(){ alert(&quot;some error occurred&quot;) },
        success:function(response){ alert(response); }
       });
    
    });


Does anyone know how to work more with timeout?
 

Determine if $.ajax error is a timeout

Okay so basically I want to have a bit of javascript on a page that somehow attaches some kind of global event listener that can detect and do something if an ajax request is made (without directly calling it from the call), regardless of how the ajax call is made. 

I figured out how to do this with jquery - if the ajax request is being done _by_ jquery. Here is an example code for this:

    $.post(
      // requested script
      &#39;someScript.php&#39;, 
      // data to send
      {
        &#39;foo&#39; : &#39;bar&#39;,
        &#39;a&#39; : &#39;b&#39;
      },
      // receive response
      function(response){
        // do something
      }
    ); // .post

    // global event listener    
    $(document).ajaxSend(
      function(event,request,settings){
        alert(settings.url); // output: &quot;someScript.php&quot;
        alert(settings.data); // output: &quot;foo=bar&amp;a=b&quot;
      }
    );

With this code, regardless of where/how I call $.post(..), the global event listener will trigger. It also works if I use $.get or $.ajax (any jquery ajax methods), regardless of how/when I call it (attached as an onclick, on page load, whatever).  

However, I want to be able to extend this listener to trigger regardless of what js framework is used, or even if no framework is used.  So for instance if I were to ***also*** have on a page the following code (generic ajax code from w3schools):

    function loadXMLDoc()
    {
    if (window.XMLHttpRequest)
      {// code for IE7+, Firefox, Chrome, Opera, Safari
      xmlhttp=new XMLHttpRequest();
      }
    else
      {// code for IE6, IE5
      xmlhttp=new ActiveXObject(&quot;Microsoft.XMLHTTP&quot;);
      }
    xmlhttp.onreadystatechange=function()
      {
      if (xmlhttp.readyState==4 &amp;&amp; xmlhttp.status==200)
        {
        document.getElementById(&quot;myDiv&quot;).innerHTML=xmlhttp.responseText;
        }
      }
    xmlhttp.open(&quot;GET&quot;,&quot;test.txt&quot;,true);
    xmlhttp.send();
    }

And then I have on some random link an onclick call to that function, my global ajax event listener should be able to ***also*** detect this request.  Well I added that code to my page and attached it to a random link&#39;s onclick (yes, the code itself works), but the jquery &quot;global event listener&quot; code above failed to detect that call. 

I did some more digging and I know I can basically save the object to a temp object and overwrite the current object with a &quot;wrapper&quot; object that will call a specified function and then call the temp function, but this requires me to know ahead of time the original object being created/used. But I won&#39;t always know that ahead of time...

So...is this possible? Is there some way to detect an ajax get/post request was made, regardless of whether it was done with a generic object or from xyz framework?  Or am I just going to have to make duplicate code to handle each framework and also know ahead of time the ajax object(s) being created/used?

edit:

I forgot to mention that it is not enough to detect that a request occurred. I also need to capture the data being sent in the request.  The link provided in the comments below will help figure out if &quot;a&quot; request was made, but not get the data sent.  p.s. - the answer provided in the link below is not very clear, at least to me anyways.  


JavaScript detect an AJAX event

I need to set a cookie before I issue a request to a Web site using Fiddler. How do I do this?

How can I set a cookie in a request using Fiddler?

I have two webapps WebApp1 and WebApp2 in two different domains.

1. I am setting a cookie in WebApp1 in the HttpResponse.
2. How to read the same cookie from HttpRequest in WebApp2?

I know it sounds weird because cookies are specific to a given domain, and we can&#39;t access them from different domains; I&#39;ve however heard of CROSS-DOMAIN cookies which can be shared across multiple  webapps. How to implement this requirement using CROSS-DOMAIN cookies?

Note: I am trying this with J2EE webapps          

Cross-Domain Cookies

I want to be able to set a single cookie, and read that single cookie with each request made to the nodejs server instance. Can it be done in a few lines of code, without the need to pull in a third party lib?

    var http = require(&#39;http&#39;);
    
    http.createServer(function (request, response) {
      response.writeHead(200, {&#39;Content-Type&#39;: &#39;text/plain&#39;});
      response.end(&#39;Hello World\n&#39;);
    }).listen(8124);
    
    console.log(&#39;Server running at http://127.0.0.1:8124/&#39;);

Just trying to take the above code directly from nodejs.org, and work a cookie into it.

Get and Set a Single Cookie with Node.js HTTP Server

Is there any way to, with help of Javascript, list all cookies associated with the current page? That is, if I don&#39;t know the names of the cookies but want to retrieve all the information they contain.

How can I list all cookies for the current page with Javascript?

How are cookies passed in the HTTP protocol?

Content Type	Original Author	Original Content on Stackoverflow
Question	Billworth Vandory	View Question on Stackoverflow
Solution 1 - Ajax	Strelok	View Answer on Stackoverflow
Solution 2 - Ajax	this. __curious_geek	View Answer on Stackoverflow
Solution 3 - Ajax	Bogdan Stăncescu	View Answer on Stackoverflow
Solution 4 - Ajax	Phil	View Answer on Stackoverflow

Can an AJAX response set a cookie?

Ajax Problem Overview

Ajax Solutions

Solution 1 - Ajax

Solution 2 - Ajax

Solution 3 - Ajax

Solution 4 - Ajax

Is it possible to declare two variables of different types in a for loop?

Java, How do I get current index/key in "for each" loop

Attributions