(function(window, undefined){function jQuery(sel){return new jQuery.prototype.init(sel);}jQuery.prototype = {constructor: jQuery,init: function(sel){if(typeof sel === 'string'){var that = this;var nodeList = document.querySelectorAll(sel);Array.prototype.forEach.call(nodeList, function(val, i){that[i] = val;})this.selector = sel;this.length = nodeList.length;}},show: function(){Array.prototype.forEach.call(this, function(node){//if(node.style) continue; //textnode沒有style//刪除style上的display:nonevar display = node.style.display;if(display === 'none'){//dispaly置為空后，css如果有display則css的生效//否則默認的生效node.style.display = '';}//元素display值為非默認值情況，需要還原為oldDisplay：div->display:inline-block//或 檢測css上的display是否為noneif(node.style.display==='' || isHidden(node)){//有oldDispaly則設置if(node.oldDisplay) node.style.display = node.oldDisplay;//沒有則設置為元素默認值或元素當前值else node.style.display = getDisplay(node);}})//鏈式調用return this;},hide: function(){Array.prototype.forEach.call(this, function(node){if(!isHidden(node)) {//jQuery使用其cache機制存儲信息，這里簡化一下//直接掛載在對應的dom下node.oldDisplay = getDisplay(node);node.style.display = 'none';}})return this;}}function getDisplay(node){var display = window.getComputedStyle(node, null).getPropertyValue('display');if(display === 'none'){var dom = document.createElement(node.nodeName);//插入到body中document.body.appendChild(dom);//即可獲取到元素display的默認值var display = window.getComputedStyle(dom, null).getPropertyValue('display');document.body.removeChild(dom);}return display;}function isHidden(node) {//忽略未append進document的元素這種隱藏情況：$('<div>block</div>')未appendreturn window.getComputedStyle(node, null).getPropertyValue('display') === 'none';}jQuery.prototype.init.prototype = jQuery.prototype;window.$ = jQuery;})(window);