CODEWITHSUNDEEP
javascript
simply-put
simply-put

Reputation: 1088

Ajax Call Sequence in a function

I have a little question. say i have a js function

$(function() {
 $(".button").click(function(){ 
 var id=$(this).attr('id');
 var dataString = 'id='+ id ;
 $.ajax({
   type: "POST",
   url: "download_number.php",
   data: dataString,
   cache: false,
   success: function(html)
   {
     $("#div_"+id).html(html);
   }  });
   window.open('File_download.php?file_id='+id, '_blank' );
  });

as you can see window.open call is after $.ajax call

Does it guaratee that $.ajax call will get executed every time before the page reloads and if no then

shouldn't we declare window.open in success function?

In my opinion when there is slow response from server the page will reload first and it may happen that $.ajax call will be interrupted by window.open function

but i get a downvote for the same reason here stackoverflow.com/questions/12908138/how-to-get-the-id-or-name-of-related-file/

And Thanks for making my belief stronger

Upvotes: 0

Views: 208

Answers (2)

Felix
Felix

Reputation: 789

In your example, the window.open function will always (!) be called before the success callback function given to the ajax call. Ajax traffic is always asynchronous, whereas the window.open function resides in the synchronous JS <script> tag.

Since JavaScript is single-threaded, all synchronous statements will always be executed before any asynchronous functionality like ajax setTimeout animate etc. 

$.ajax({
   type: "POST",
   url: "download_number.php",
   data: dataString,
   cache: false,
   success: function(html) { // asynchronous functionality
     $("#div_"+id).html(html);
   }  
}); 
// within synchronous script statements
window.open('File_download.php', '_blank' );

Upvotes: 1

Bergi
Bergi

Reputation: 665090

Yes, Ajax is asynchronous so you will open that window right after you started the XHR process. To download the processed data, open the new window from the success callback. Yet I'm not sure what you mean by "before the page reloads" - there is no code which does that.

Also I don't know how your server behaves, the file_download.php seems to be independent from your ajax call. Shouldn't you pass the download_number you received via ajax in there?

Upvotes: 1

Related Questions