JQuery 获取Dom元素的实例讲解

(function (window) {var arr = [];var VP = function (selector, context) {return new VP.fn.init(selector, context);}VP.fn = VP.prototype = {constructor: VP,init: function (selector, context) {var _document = window.document, elem, mark = selector.charAt(0);if (mark == '#') {elem = _document.getElementById(selector.substring(1));if (elem) {this[0] = elem;this.length = 1;}}return this;},splice: arr.splice,};VP.extend = VP.fn.extend = function () {var options, name, src, copy, copyIsArray, clone,target = arguments[0] || {},i = 1,length = arguments.length,deep = false;if (typeof target === "boolean") {deep = target;target = arguments[i] || {};i++;}if (typeof target !== "object" && !VP.isFunction(target)) {target = {};}if (i === length) {target = this;i--;}for (; i < length; i++) {if ((options = arguments[i]) != null) {for (name in options) {src = target[name];copy = options[name];if (target === copy) {continue;}if (deep && copy && (VP.isPlainObject(copy) ||(copyIsArray = VP.isArray(copy)))) {if (copyIsArray) {copyIsArray = false;clone = src && VP.isArray(src) ? src : [];} else {clone = src && VP.isPlainObject(src) ? src : {};}target[name] = VP.extend(deep, clone, copy);} else if (copy !== undefined) {target[name] = copy;}}}}return target;};VP.fn.extend({get: function () {return this[0];},});VP.fn.init.prototype = VP.fn;window.VP = VP;})(window);