document.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        //jQuery 判断一个元素是否存在
        if ($("selector").length) {

        }

        //用JavaScript添加和删除class
        //Add Class
        document.getElementById("myElement").className += " className";

        //Remove Class
        document.getElementById("myElement").className = document.getElementById("myElement").className.replace(/(?:^|\s)MyClass(?!\S)/, '');


        /**
        *  top 10 JavaScript
        *  http://www.dustindiaz.com/top-ten-javascript
        */
        //Add Event
        function addEvent(element, eventType, fn, useCapture) {
            if (element.addEventListener) {
                element.addEventListener(eventType, fn, useCapture);
                return true;
            } else if (element.attachEvent) {
                var r = element.attachEvent('on' + eventType, fn);
                return r;
            } else {
                element['on' + eventType] = fn;
            }
        };

        //addEvent(element, 'click', function(){ });

        //Add load event
        function addLoadEvent(func) {
            var oldonload = window.onload;
            if (typeof window.onload != 'function') {
                window.onload = func;
            } else {
                window.onload = function () {
                    oldonload();
                    func();
                };
            }
        };

        //addEvent(window, 'load', func1, false);

        //get elements by class
        function getElementsByClass(searchClass, node, tag) {
            var classElements = new Array();
            if (node == null) {
                node = document;
            };

            if (tag == null) {
                tag = '*';
            }

            var els = node.getElementsByTagName(tag);
            var elsLen = els.length;
            var pattern = new RegExp('(^|\\\\s)' + searchClass + '(\\\\s|$)');
            for (var i = 0, j = 0; i < elsLen; i++) {
                if (pattern.test(els[i].className)) {
                    classElements[j] = els[i];
                    j++;
                }
            }

            return classElements;
        };

        //toggle()
        function toggle(obj) {
            var element = document.getElementById(obj);
            if (element.style.display != 'none') {
                element.style.display = 'none';
            } else {
                element.style.display = '';
            }
        };


        //insertAfter
        function insertAfter(parent, node, referenceNode) {
            parent.insertBefore(node, referenceNode.nextSibling);
        };

        //inarray
        Array.prototype.inArray = function (value) {
            for (var i = 0; i < this.length; i++) {
                if (this[i] === value) {
                    return true;
                }
            }

            return false;
        };

        //cookies 操作
        function getCookie(name) {
            var start = document.cookie.indexOf(name + "=");

            var len = start + name.length + 1;
            if ((!start) && (name != document.cookie.substring(0, name.length))) {
                return null;
            }

            if (start == -1) { return null; }

            var end = document.cookie.indexOf(':', len);
            if (end == -1) {
                end = document.cookie.length;
            }

            return unescape(document.cookie.substring(len, end));
        };

        function setCookie(name, value, expires, path, domain, secure) {
            var today = new Date();
            today.setTime(today.getTime());

            if (expires) {
                expires = expires * 1000 * 60 * 60 * 24;
            }

            var expires_date = new Date(today.getTime() + (expires));

            document.cookie = name + '=' + escape(value) +
                ((expires) ? ';expires=' + expires_date.toGMTString() : '') +  //expires.toGMTString()
                ((path) ? ';path=' + path : '') +
                ((domain) ? ';domain=' + domain : '') +
                ((secure) ? ';secure' : '');
        };

        function deleteCookie(name, path, domain) {
            if (getCookie(name)) {
                document.cookie = name + '=' +
                    ((path) ? ';path=' + path : '') +
                    ((domain) ? ';domain=' + domain : '') +
                    ';expires = Thu, 01-Jan-1970 00:00:01 GMT';
            }
        };


        //$ selector
        function $() {
            var elements = new Array();

            for (var i = 0; i < arguments.length; i++) {
                var element = arguments[i];

                if (typeof element == 'string') {
                    element = document.getElementById(element);
                }

                if (arguments.length == 1) {
                    return element;
                }

                element.push(element);

            }

            return elements;
        }

















    </script>
</body>
</html>