本文学习jQuery源码，封装了each、map、toArray、get以及，一些基本DOM操作方法

(function (window) {
    var arr = [];
    var push = arr.push;
    var slice = arr.slice;
    function MHQ(selector) {
        return new MHQ.fn.init(selector);
    }
    MHQ.fn = MHQ.prototype = {
        constructor: MHQ,
        length: 0,
        init: function (selector) {
            // 判断选择器类型
            if (!selector) return this;
            if (typeof selector === "string") {
                if (selector.charAt(0) === "<") {
                    push.apply(this, parseHTML(selector));
                    return this;
                } else {
                    push.apply(this, document.querySelectorAll(selector));
                    return this;
                }
            }
            if (typeof selector === "function") {
            } 
           if (selector.nodeType) { 
                this[0] = selector;
                this.length = 1;
                return this;
            }
            if (selector.constructor.name === MHQ) {
                return selector;
            }
            if (selector.length >= 0) {
                push.apply(this, selector);
            } else {
                this[0] = selector;
                this.length = 1;
            }
        }
    };
    MHQ.fn.init.prototype = MHQ.fn;
    MHQ.extend = MHQ.fn.extend = function (obj) {
        var k;
        for (k in obj) {
            this[k] = obj[k];
        }
    };
    MHQ.fn.extend({
        each: function (callback) {
            return MHQ.each(this, callback);
        },
        map: function (callback) {
            return MHQ.map(this, callback);
        }
    });
    MHQ.extend({
        each: function (obj, callback) {
            var i,
                    len = obj.length,
                    isArray = len >= 0;
            if (isArray) {
                for (i = 0; i < len; i++) {
                    if (callback.call(obj[i], i, obj[i]) === false) break;
                }
            } else {
                for (i in obj) {
                    if (callback.call(obj[i], i, obj[i]) === false) break;
                }
            }
            return obj;
        },
        map: function (obj, callback) {
            var i,
                    len = obj.length,
                    isArray = len >= 0, 
                    result,
                    ret = [];
            if (isArray) {
                for (i = 0; i < len; i++) {
                    result = callback(obj[i], i);
                    if (result != null) {
                        ret.push(result);
                    }
                }
            } else {
                for (i in obj) {
                    result = callback(obj[i], i);
                    if (result != null) {
                        ret.push(result);
                    }
                }
            }
            return ret;
        },
        next: function ( dom ) {
            var node = dom;
            while( node = node.nextSibling ) {
                if ( node.nodeType === 1 ) {
                    return node;
                }
            }
            return null;
        }
    });
    function parseHTML(htmlStr) {
        var div = document.createElement("div"),
                i = 0,
                nodeArr = []; 
       div.innerHTML = htmlStr;
        for (; i < div.childNodes.length; i++) {
            nodeArr.push(div.childNodes[i]);
        }
        return nodeArr;
    }
    MHQ.fn.extend({
        toArray: function () {
            return slice.call(this);
        },
        get: function (index) {
            if (index === undefined) {
                return this.toArray();
            } else {
                return this[index > 0 ? index : this.length + index];
            }
        }
    });
    // DOM元素操作
    MHQ.fn.extend({
        appendTo: function (selector) {
            var i,
                    j,
                    tmpObj,
                    ret = [],
                    destinationObj = MHQ(selector);
            for (i = 0; i < this.length; i++) {
                for (j = 0; j < destinationObj.length; j++) {
                    tmpObj = j === destinationObj.length - 1 ? this[i] : this[i].cloneNode(true);
                    ret.push(tmpObj);
                    destinationObj[j].appendChild(tmpObj);
                }
            }
            return this.pushStack(ret);
        },
        prependTo: function (selector) {
            // 将 this[i] 加入到 selector[j] 中, 链会破坏
            // MHQ( selector ).prepend( this );
            var tmpObj, ret = [],
                    i, j,
                    destinationObj = MHQ(selector);
            for (i = 0; i < this.length; i++) {
                for (j = 0; j < destinationObj.length; j++) {
                    tmpObj = j === destinationObj.length - 1 ? this[i] : this[i].cloneNode(true);
                    ret.push(tmpObj);
                    destinationObj[j].insertBefore(tmpObj, destinationObj[j].firstChild);
                }
            }
            return this.pushStack(ret);
        },
        prepend: function (selector) {
            MHQ(selector).appendTo(this);
            return this;
        },
        append: function (selector) {
            // 将 selector[j] 加到 this[i] 中
            // 不会造成链破坏
            MHQ(selector).appendTo(this);
            return this;
        },
        next: function () {
            /*
             var ret = [];
             this.each(function () {
             ret.push( this.nextElementSibling );
             });
             return this.pushStack( ret );
             */
            return this.pushStack(
                    this.map(function (v) {
                        return v.nextElementSibling;
                    }));
        },
        remove: function () {
            this.each(function () {
                this.parentNode.removeChild(this);
            });
        }
    });
    // 恢复链
    MHQ.fn.extend({
        end: function () {
            return this.prevObj || this;
        },
        pushStack: function (array) {
            var newObj = MHQ(array);
            newObj.prevObj = this;
            return newObj;
        }
    });
    window.MHQ = window.M = MHQ;})(window);

博客原文地址：
http://www.cnblogs.com/hongqin/