How to reference a variable dynamically in javascript

Question

I am trying to reference a variable dynamically in javascript

The variable I am trying to call is amtgc1# (where # varies from 1-7)

I am using a while statement to loop through, and the value of the counting variable in my while statement corresponds with the last digit of the variable I am trying to call.

For Example:

            var inc=3;
            var step=0;
            while(step < inc){
                var dataString = dataString + amtgc1#;
                var step = step+1;
            }

Where # is based on the value of the variable "step". How do I go about doing this? Any help is appreciated! Thanks!!

Answer 1

The only way you can do this (afaik) is to throw all of your amtgc1# vars in an object such as:

myVars = {
  amtgc1: 1234,
  amtgc2: 12345,
  amtgc3: 123456,
  amtgc4: 1234567
};

Then you can reference it like

myVars["amtgc" + step];

Answer 2

Rather than defining amtgc1[1-7] as 7 different variables, instantiate them as an array instead. So your server code would emit:

var amtgc1 = [<what used to be amtgc11>,<what used to be amtgc12>, ...insert the rest here...];

Then, you can refer to them in your loop using array syntax:

var dataString = dataString + amtgc1[step];

Answer 3

How about:

var dataString = dataString + eval('amtgc1' + step);

Answer 4

Not tested, but can't see why you can't do this...

$('#amtgc1' + step).whatever();

Answer 5

If your amtgc1* variables are defined as a property of an object, you can reference them by name. Assuming they are declared in the global scope, they will be members of the window object.

        var inc=7; 
        var step=0; 
        while(step < inc){ 
            var dataString = dataString + window['amtgc1'+(step+1)]; 
            var step = step+1; 
        } 

If they are defined in a different scope (within a function) but not belonging to any other object, you're stuck with eval, which is generally considered bad.

also, hooray for loops!

        var inc=7; 
        for ( var step=0; step < inc; step++ ){ 
            var dataString = dataString + window['amtgc1'+(step+1)]; 
         }