lib/Ext/Component.js
function(cls, prefix, suffix) {
        var oldCls = this.getCls(),
            newCls = (oldCls) ? oldCls.slice() : [],
            ln, i;

        prefix = prefix || '';
        suffix = suffix || '';

        if (typeof cls == "string") {
            newCls = Ext.Array.remove(newCls, prefix + cls + suffix);
        } else {
            ln = cls.length;
            for (i = 0; i < ln; i++) {
                newCls = Ext.Array.remove(newCls, prefix + cls[i] + suffix);
            }
        }

        this.setCls(newCls);
    }
function(cls, prefix, suffix) {
        var oldCls = this.getCls(),
            newCls = (oldCls) ? oldCls.slice() : [],
            ln, i;

        prefix = prefix || '';
        suffix = suffix || '';

        if (typeof cls == "string") {
            newCls = Ext.Array.remove(newCls, prefix + cls + suffix);
        } else {
            ln = cls.length;
            for (i = 0; i < ln; i++) {
                newCls = Ext.Array.remove(newCls, prefix + cls[i] + suffix);
            }
        }

        this.setCls(newCls);
    }
Removes the given CSS class(es) from this Component's rendered element.
@param {String} cls The class(es) to remove.
@param {String} [prefix=""] Optional prefix to prepend before each class.
@param {String} [suffix=""] Optional suffix to append to each class.