Is there a way to use a variable by combining two other variables in JavaScript?

Question

My problem is best explained in code form.

<!DOCTYPE HTML>
<html>
<head></head>
<body>
<script>
var x = "x";
var y = 1;
var x1 = "something";
alert(x+y);
</script>
</body>
</html>

I would then want it to alert the value of x1, which in this case would be "something". As you can see this obviously doesn't work but how would you do this in JavaScript? It would be much apreciated if you could keep you answer as simple as possible, as I'm new to programming.

EDIT:

I just want to clarify here that the above code isn't actually my project. I was just trying to explain my problem in a simple way so everyone would understand me. I'll put an example of my actual project code below.

value_+x=document.getElementById('square_+x');

Again I know this wont work but would you change this to

value_4=document.getElementById('square_4');

If x happend to be 4?

You have a serious misconception here: What you are manipulating by writing `x+y` is the *value* of the variables and **not** their names. — Darkhogg, Oct 28 '13 at 16:43
See http://stackoverflow.com/questions/5117127/javascript-dynamic-variable-name — j08691, Oct 28 '13 at 16:43

score 4 · Accepted Answer · answered Oct 28 '13 at 16:43

4

If it's a global window variable, you can do

window[x+y];

answered Oct 28 '13 at 16:43

Jeff Storey

56,312
72
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Ick. Globals. Best avoided. – Quentin Oct 28 '13 at 16:44
Thank you for the answer but when do you know if it's a global window variable? – Lasse Møldrup Oct 29 '13 at 14:36
Have you declared it as one? Is your variable declaration in the global namespace? – Jeff Storey Oct 29 '13 at 14:45
I guess it isn't then. I will try eval(x+y) in my project. By the way why are people saying that eval is a bad idea? – Lasse Møldrup Oct 29 '13 at 15:05
By the way your code looks, it is in the global namespace. If the `var` is not within a `function` or a property of another object, then it is global. As for eval, that's been discussed at length http://stackoverflow.com/questions/86513/why-is-using-the-javascript-eval-function-a-bad-idea – Jeff Storey Oct 29 '13 at 15:07
I think I wasn't clear enough when asking my question so I've clarified it above. – Lasse Møldrup Oct 29 '13 at 15:24
Same principle applies - see this fiddle http://jsfiddle.net/Gfax6/ – Jeff Storey Oct 29 '13 at 15:30

score 0 · Answer 2 · answered Oct 28 '13 at 16:53

0

this ll help you provided the documentation as well alert(eval(x+y))

answered Oct 28 '13 at 16:53

Hisham

455
4
16

Is there a way to use a variable by combining two other variables in JavaScript?

2 Answers2