原生js addclass,hasClass,removeClass,toggleClass的兼容

(function (window) {

    'use strict';

    // class helper functions from bonzo https://github.com/ded/bonzo

    function classReg(className) {
        return new RegExp("(^|\\s+)" + className + "(\\s+|$)");
    }

    // classList support for class management
    // altho to be fair, the api sucks because it won't accept multiple classes at once
    var hasClass,
    addClass,
    removeClass;

    if ('classList' in document.documentElement) {
        hasClass = function (elem, c) {
            return elem.classList.contains(c);
        };
        addClass = function (elem, c) {
            elem.classList.add(c);
        };
        removeClass = function (elem, c) {
            elem.classList.remove(c);
        };
    } else {
        hasClass = function (elem, c) {
            return classReg(c).test(elem.className);
        };
        addClass = function (elem, c) {
            if (!hasClass(elem, c)) {
                elem.className = elem.className + ' ' + c;
            }
        };
        removeClass = function (elem, c) {
            elem.className = elem.className.replace(classReg(c), ' ');
        };
    }

    function toggleClass(elem, c) {
        var fn = hasClass(elem, c) ? removeClass : addClass;
        fn(elem, c);
    }

    var classie = {
        // full names
        hasClass : hasClass,
        addClass : addClass,
        removeClass : removeClass,
        toggleClass : toggleClass,
        // short names
        has : hasClass,
        add : addClass,
        remove : removeClass,
        toggle : toggleClass
    };

    // transport
    if (typeof define === 'function' && define.amd) {
        // AMD
        define(classie);
    } else {
        // browser global
        window.classie = classie;
    }

})(window);

经测试，兼容IE8以下；

参考：https://github.com/ded/bonzo，