Possible Duplicate:
How can I get jQuery to perform a synchronous, rather than asynchronous, AJAX request?
Get a variable after ajax done
The two alert functions in the following code returns different results. I am trying to get the second to evaluate true too.. Any help is appreciated.. Thanks..
var array;
$.get('php/getstocklist.php', function(data){
array = data;
alert($.isArray(array)); //alerts true
}, "json");
alert($.isArray(array)); //alerts false
The problem is that the $.get is async. The var is global as you have it now. It just isn't defined because your second alert runs immediately before the ajax has returned and run its success callback.
In order to use it outside the the callback you would need to poll a variable to make sure the result has been assigned... but then you are essentially using a fake callback so it makes more sense to restructure your code and do it the normal way :-)
Here's what's happening:
// This variable _is_ global. However, it's current value is undefined
var array;
$.get('php/getstocklist.php', function(data){
// After this runs, _now_ array has data in it
array = data;
// thus causing $.isArray to return true here.
alert($.isArray(array)); //alerts true
}, "json");
// This call happens BEFORE the callback to the $.get call,
// so as of this line, array is still undefined, which results in
// the $.isArray call returning false.
alert($.isArray(array)); //alerts false
Javascript is a heavy asynchronous language. You have to kind of break away from procedure thinking, and instead think in terms of passing bits of code around to be executed later (those are callbacks).
data assigned to it. The function that assigns the value doesn't run until the HTTP response arrives.data. You could remove the entire ajax call and it would give the same result.
The second alert executes before the first because the $.get callback executes asynchronously. If you want the second alert to return true, you should use a jQuery Deferred object like so:
var array;
deferred = $.get('php/getstocklist.php', function(data){
array = data;
alert($.isArray(array)); //alerts true
}, "json");
// alerts true if $.get succeeded
deferred.done(function () { alert($.isArray(array)); });
The callback you pass to done will fire when the asynchronous $.get call returns.
If I understand you right why can't you
$.getJSON('php/getstocklist.php', function(data){
dosomething(data);
});
function dosomething(data) {}
Its a bit off a fudge but try setting using that will break your variable out off the request and make it global
window.array = data;
alert($.isArray(window.array));
dataassigned to it. The one on the last line is executed before the HTTP response comes back so is stillundefined.