operate class attribute

classTool.js

Element.prototype.hasClassName = function (a) {
    return new RegExp("(?:^|\\s+)" + a + "(?:\\s+|$)").test(this.className);
};

Element.prototype.addClassName = function (a) {
    if (!this.hasClassName(a)) {
        this.className = [this.className, a].join(" ");
    }
};

Element.prototype.removeClassName = function (b) {
    if (this.hasClassName(b)) {
        var a = this.className;
        this.className = a.replace(new RegExp("(?:^|\\s+)" + b + "(?:\\s+|$)", "g"), " ");
    }
};

Element.prototype.toggleClassName = function (a) {
  this[this.hasClassName(a) ? "removeClassName" : "addClassName"](a);
};