Passing object property

Question

Working on my little JS framework. Trying to create a toggle method. This is the code:

function $elect(id) {
    if (!(this instanceof $elect)) {
        return new $elect(id);
    }
    this.elm = document.getElementById(id);
}

$elect.prototype = {
    toggle:     function (prop, val1, val2) {
                    if (this.elm.style.prop != val2) {
                        this.elm.style.prop = val2;
                    } else {
                        this.elm.style.prop = val1;
                    }
                }
}

window.$elect = $elect;

And using $elect(id).toggle('background', 'red', 'blue') to call it. But of course this won't work. I'm trying to find a way to hmm... how do I say it? I want to pass 'background' to this.elm.style.prop so I can also use the other css properties. How do I replace prop in this.elm.style.prop with the parameter I'm passing?

Answer 1

you can reference a key in an object with

object[key]

where key is a string.

So in your case, it'd be

this.elm.style[prop]

http://jsfiddle.net/ZJWdA/
Here's an example.