Javascript Array inside Array - how can I call the child array name?

I would create an object like this:

var options = { 
    size: ["S", "M", "L", "XL", "XXL"],
    color: ["Red", "Blue", "Green", "White", "Black"]
};


alert(Object.keys(options));

To access the keys individualy:

for (var key in options) {
    alert(key);
}

P.S.: when you create a new array object do not use new Array use [] instead.

you can get using key value something like this :

var size = new Array("S", "M", "L", "XL", "XXL");
var color = new Array("Red", "Blue", "Green", "White", "Black");
var options = new Array(size, color);

var len = options.length;
for(var i = 0; i<len; i++)
{  
 for(var key in options[i])
    {
       alert(options[i][key])
    }

}

see here : http://jsfiddle.net/8hmRk/8/

There is no way to know that the two members of the options array came from variables named size and color.

They are also not necessarily called that exclusively, any variable could also point to that array.

var notSize = size;

console.log(options[0]); // It is `size` or `notSize`?

One thing you can do is use an object there instead...

var options = {
    size: size,
    color: color
}

Then you could access options.size or options.color.