How to concatenate var names in javascript?

Question

How can i concatenate var names to declare new vars in javascript?:

var foo = 'var';
var bar = 'Name';

How can i declare variable varName?

Answer 1

WARNING: VaporCode! Off the top of my head...

window[foo + bar] = "contents of variable varName";

Does that work?

Answer 2

there may be a better way but eval should do it

eval('var ' + foo + bar);

Answer 3

Try something like:

window[foo + bar] = "whatever"; 
alert(varName);

do not use the eval function unless you are absolutely certain about what's going in. window[] is much safer if all you're doing is variable access

Answer 4

To dynamically declare a local variable (i.e. var fooName), I guess you could use eval:

eval('var ' + foo + bar);

Best to avoid eval though, if you can avoid it (see related question).

A better way is to set an object property. Defining a global variable is equivalent to setting a property on the global object window:

window[foo+bar] = 'someVal';

You can substitute window for another object if appropriate.

Answer 5

Locally:

this[foo+bar] = true;

Globally:

window[foo+bar] = true;