Easily alter CSS rules via JS

CssRule.js

// Allows programmatic altering of CSS rules. Turn this class into a flyweight by enabling modification of the underlying rule property.
function CssRule (selector, stylesheet) {
    var rules = stylesheet.rules,
        len = rules.length,
        i = 0,
        rule = null;

    for (i; i < len; i++) {
        rule = rules[i];
        if (rule.selectorText === selector) {
            this.rule = rule;            
            break;
        }
    }
}

CssRule.prototype = {
    rule: null,
    set: function (key, value) {
        this.rule.style[key] = value;
        return value;
    },
    get: function (key) {
        return this.rule.style[key];
    },
    destroy: function () {
        delete this.rule;
    }
};

/*
Example:
<style type='text/css'>
.anim {
    -webkit-transition-duration:300ms;
}
</style>
<script>
var anim = new CssRule('.anim', document.stylesheets[0]);
anim.get('webkitTransitionDuration'); // '300ms'
anim.set('webkitTransitionDuration', '100ms'); // '100ms'
</script>
*/