[SOLVED] Exposing a feebnack value from withing an AJAX call-back function...

ButterflyMelissa · 11-21-2013, 11:50 AM

Hi all,

Please consider the following snippet:

Code:

<script>
	var aValue
	
	function dothis()
	{
         getID("peter","pan");
         console.log(aValue);	
        }
	
	function getID(a,b)
	{
	$.post('getID.php', {aname: a, apass: b},
	function (fbdata)
		{
			aValue = fbdata;
		}
	);				
	}
</script>

The JS function doThis() is called upon the load from a <body> tag, it in turn calls the getID() function, and AJAX call to a PHP script on the server. Though the variable aValue is declared globally, it comes back as undefined. How do I expose the results from the call-back function un the $.post call?
PLease consider I'm learningt he ropes here...
Thank you for a reply...
Thor

Guttorm · 11-21-2013, 12:13 PM

Are you sure the ajax call doesn't fail? If it does, your function will not be called. If you add alert(fbdata) or console.log(fbdata) what is it?

ButterflyMelissa · 11-21-2013, 12:26 PM

if I do a condole feeb dicectly in the caal-back I get the ID...

Code:

<script>
	var aValue
	
	function dothis()
	{
         getID("peter","pan");
         console.log(aValue);	
        }
	
	function getID(a,b)
	{
	$.post('getID.php', {aname: a, apass: b},
	function (fbdata)
		{
			aValue = fbdata;
                        console.log(aValue);
		}
	);				
	}
</script>

If I do a feedback on the hi-lited spot, I get the info back, beyond the call-back, it's lost ergo "undefined" - the PHP does work...

Thanks for helping out

Thor

Edit - the result is the same even if the variable is declared in an included file...

Guttorm · 11-22-2013, 05:49 AM

Then I guess it's because ajax calls are asyncronous. In your second example, do you get "undefined" in the console before the actual value? The function getID returns first, and your anonymous function is called when the response from the ajax call is ready.

You can change it to be syncronous instead.

http://stackoverflow.com/questions/1...ronous-ajax-re

ButterflyMelissa · 11-24-2013, 03:16 PM

Thanks for the input! In act, the whole thing does work...just...I dont know how to us it

- the call is made, and the PHP works in the background, in the mean time, the JavaScript moves on, extracts the value that is yet to arrive from the server,, but before it does...it's as yet undefined. As suggested, setting the call to syncronous (async:false) solves this.
Of course, this is not what AJAX is meant for, but at this critical stage, the info is needed and the call has to halt there to wait for the info to come through...
Marking this as solved
Thor