lib/Ext/dom/Element.style.js
function(names, prefix, suffix) {
        if (!names) {
            return this;
        }

        if (!this.isSynchronized) {
            this.synchronize();
        }

        if (!suffix) {
            suffix = '';
        }

        var dom = this.dom,
            map = this.hasClassMap,
            classList = this.classList,
            SEPARATOR = this.SEPARATOR,
            i, ln, name;

        prefix = prefix ? prefix + SEPARATOR : '';
        suffix = suffix ? SEPARATOR + suffix : '';

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

        for (i = 0, ln = names.length; i < ln; i++) {
            name = prefix + names[i] + suffix;

            if (map[name]) {
                delete map[name];
                Ext.Array.remove(classList, name);
            }
        }

        dom.className = classList.join(' ');

        return this;
    }
function(names, prefix, suffix) {
        if (!names) {
            return this;
        }

        if (!this.isSynchronized) {
            this.synchronize();
        }

        if (!suffix) {
            suffix = '';
        }

        var dom = this.dom,
            map = this.hasClassMap,
            classList = this.classList,
            SEPARATOR = this.SEPARATOR,
            i, ln, name;

        prefix = prefix ? prefix + SEPARATOR : '';
        suffix = suffix ? SEPARATOR + suffix : '';

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

        for (i = 0, ln = names.length; i < ln; i++) {
            name = prefix + names[i] + suffix;

            if (map[name]) {
                delete map[name];
                Ext.Array.remove(classList, name);
            }
        }

        dom.className = classList.join(' ');

        return this;
    }
Removes the given CSS class(es) from this Element.
@param {String} names The CSS class(es) to remove from this element.
@param {String} [prefix=''] Prefix to prepend to each class to be removed.
@param {String} [suffix=''] Suffix to append to each class to be removed.