Finding similarly named variables using jquery

Question

My code is below

<script>
ball1 = "this is ball1";
ball2 = "this is ball2";
ball3 = "this is ball3";
bat = "this is not a ball";

var arr = $("[name^='ball']");
alert(arr.length);
</script>

I want to get all the variables starting with the string 'ball'. How do I do it? The above code gives the arr.length as 0. Is my code correct?

they are javascript variables... not html objects with the name attribute that starts with ball — Adween, Mar 05 '14 at 21:02
I've read [your previous question](http://stackoverflow.com/q/22157209/1636522) and it makes things a bit more clear. Two questions remain though : which variables do you want to access - globally or locally defined variables - and *why*? I believe the *why* is important here to know how to answer properly. — , Mar 05 '14 at 21:31
I've read all of your previous questions, now I wonder whether your problem has something to do with the following one : http://stackoverflow.com/q/19526456/1636522. Let me know. — , Mar 05 '14 at 21:49
@procrastinator I have explained in a new question as it was difficult to explain here in comments. http://stackoverflow.com/questions/22228756/accessing-custom-defined-variable-object-in-javascript-in-for-in-loop — sam, Mar 06 '14 at 16:41

score 2 · Answer 1 · 2014-03-05T21:34:39.667

jQuery is intended to query the DOM tree. Anyway, try this :

var r = /^ball/,
    balls = [];
for (var k in window) {
    r.test(k) && balls.push(window[k]);
}

Notice that window (uppermost scope) is implicitely populated :

<script>
var ball1 = '1'; // global variable
window.ball1; // '1'
</script>

However, this is not true if you're working inside of a function :

function f() { 
    var ball1 = '1'; // local variable
    window.ball1; // undefined
}
f();
window.ball1; // undefined;

In this case, there no way to access ball1 from the outside.

This gives me an empty array in IE8. Any solution for that? – sam Mar 05 '14 at 21:14 — sam, Mar 05 '14 at 21:14

score 0 · Answer 2 · answered Mar 05 '14 at 21:04

0

That will give 0 as

$("[name^='ball']") will search the DOM with attribute 'name' not Variable name

answered Mar 05 '14 at 21:04

Makrand

587
5
14

score 0 · Answer 3 · answered Mar 05 '14 at 21:18

As an alternative to procrastinator's elegant javascript solution. If you wanted to do it using jquery and dom objects you could do something similar to this

http://jsfiddle.net/kDy8Z/1/

<span name="newsletter"></span>
<span name="milkman"></span>
<span name="newsboy"></span>

<script>
$(function(){
    var array = $("[name^='news']");
    alert(array.length);
});
</script>

They dont have to be spans but anything with the name attribute that starts with news.

Example taken from here https://api.jquery.com/attribute-starts-with-selector/

Finding similarly named variables using jquery

3 Answers3