lib/Ext/dom/Element.style.js
function(className) {
        var map = this.hasClassMap,
            i, ln, name;

        if (typeof className == 'string') {
            className = className.split(this.spacesRe);
        }

        for (i = 0, ln = className.length; i < ln; i++) {
            name = className[i];
            if (!map[name]) {
                map[name] = true;
            }
        }

        this.classList = className.slice();
        this.dom.className = className.join(' ');
    }
function(className) {
        var map = this.hasClassMap,
            i, ln, name;

        if (typeof className == 'string') {
            className = className.split(this.spacesRe);
        }

        for (i = 0, ln = className.length; i < ln; i++) {
            name = className[i];
            if (!map[name]) {
                map[name] = true;
            }
        }

        this.classList = className.slice();
        this.dom.className = className.join(' ');
    }
Sets the specified CSS class on this element's DOM node.
@param {String/Array} className The CSS class to set on this element.