Undefined variable in JavaScript function

Question

I have the following code inside a button-click-function

var ItemID2;

$.get("http://localhost/tddd27/index.php/json/Products?ItemName="+thisID, 
          function(data){
             ItemID2=data[0].ItemID;
            },"json");

console.log(ItemID2);

after I click the button I see in the console that ItemID2 is undefined. If I use console.log(data[0].ItemID) inside the get-function I see the correct value. I think that the problem is that the execution of the function continues but Ajax has not yet retrieve the value of ItemID2. Any idea how can I fix that?

Ajax is Asynchronous. You can fix it, but i suggest instead coding around it. Fixing it means making the browser look broken. — Kevin B, May 03 '13 at 17:31
Can we please just close these as duplicates? This is asked like 30 times a day. Seriously, when this question comes up, don't vote, don't comment, don't answer. Just cast your close votes. — user229044, May 03 '13 at 17:34
Please, if a moderator is here, just close my useless question. I got it. — Avraam Mavridis, May 03 '13 at 17:38

score 2 · Answer 1 · answered May 03 '13 at 17:32

2

I think that the problem is that the execution of the function continues but Ajax has not yet retrieve the value of ItemID2.

You are right, it's an asynchronous function. You have to resume your program flow to the request's callback.

answered May 03 '13 at 17:32

bfavaretto

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score 2 · Answer 2 · answered May 03 '13 at 17:32

2

A-JAX is A-synchronous.

That is why there is a callback function.

answered May 03 '13 at 17:32

Naftali

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score 2 · Answer 3 · answered May 03 '13 at 17:32

2

Simple:

var ItemID2;

$.get("http://localhost/tddd27/index.php/json/Products?ItemName="+thisID, 
          function(data){
             ItemID2=data[0].ItemID;
             console.log(ItemID2);
            },"json");

answered May 03 '13 at 17:32

A. Wolff

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Undefined variable in JavaScript function

3 Answers3