本文實例講述了JS基於構造函數實現的菜單滑動顯隱效果。分享給大家供大家參考，具體如下：
運行效果截圖如下：
具體代碼如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><meta http-equiv="Content-Type" content="; charset=utf-8" /><title>JS樹型菜單</title><script language="javascript">function SDMenu(id) { if (!document.getElementById || !document.getElementsByTagName) return false; this.menu = document.getElementById(id); this.submenus = this.menu.getElementsByTagName("div"); this.remember = true; this.speed = 1; this.markCurrent = true; this.oneSmOnly = false;}SDMenu.prototype.init = function() { var mainInstance = this; for (var i = 0; i < this.submenus.length; i++) this.submenus[i].getElementsByTagName("span")[0].onclick = function() { mainInstance.toggleMenu(this.parentNode); }; /*if (this.markCurrent) { var links = this.menu.getElementsByTagName("a"); for (var i = 0; i < links.length; i++) if (links[i].href == document.location.href) { links[i].className = "current"; break; } }*/ if (this.remember) { var regex = new RegExp("sdmenu_" + encodeURIComponent(this.menu.id) + "=([01]+)"); var match = regex.exec(document.cookie); if (match) { var states = match[1].split(""); for (var i = 0; i < states.length; i++) this.submenus[i].className = (states[i] == 0 ? "collapsed" : ""); } }};SDMenu.prototype.toggleMenu = function(submenu) { if (submenu.className == "collapsed") this.expandMenu(submenu); else this.collapseMenu(submenu);};SDMenu.prototype.expandMenu = function(submenu) { var fullHeight = submenu.getElementsByTagName("span")[0].offsetHeight; var links = submenu.getElementsByTagName("a"); for (var i = 0; i < links.length; i++) fullHeight += links[i].offsetHeight; var moveBy = Math.round(this.speed * links.length); var mainInstance = this; var intId = setInterval(function() { var curHeight = submenu.offsetHeight; var newHeight = curHeight + moveBy; if (newHeight < fullHeight) submenu.style.height = newHeight + "px"; else { clearInterval(intId); submenu.style.height = ""; submenu.className = ""; mainInstance.memorize(); } }, 10); //this.collapseOthers(submenu); };SDMenu.prototype.collapseMenu = function(submenu) { var minHeight = submenu.getElementsByTagName("span")[0].offsetHeight; var moveBy = Math.round(this.speed * submenu.getElementsByTagName("a").length); var mainInstance = this; var intId = setInterval(function() { var curHeight = submenu.offsetHeight; var newHeight = curHeight - moveBy; if (newHeight > minHeight) submenu.style.height = newHeight + "px"; else { clearInterval(intId); submenu.style.height = ""; submenu.className = "collapsed"; mainInstance.memorize(); } }, 10);};/*SDMenu.prototype.collapseOthers = function(submenu) { if (this.oneSmOnly) { for (var i = 0; i < this.submenus.length; i++) if (this.submenus[i] != submenu && this.submenus[i].className != "collapsed") this.collapseMenu(this.submenus[i]); }};*/SDMenu.prototype.memorize = function() { if (this.remember) { var states = new Array(); for (var i = 0; i < this.submenus.length; i++) states.push(this.submenus[i].className == "collapsed" ? 0 : 1); var d = new Date(); d.setTime(d.getTime() + (30 * 24 * 60 * 60 * 1000)); document.cookie = "sdmenu_" + encodeURIComponent(this.menu.id) + "=" + states.join("") + "; expires=" + d.toGMTString() + "; path=/"; }};var myMenu;window.onload = function() { myMenu = new SDMenu("my_menu"); myMenu.init();};</script><style type="text/css"> html,body{ height:100%; margin:0; font-size:12px; } span{ background:#F0DFBE; border:1px solid #ffffff; border-left:6px solid #F2A31B; width:228px; height:23px; display:block; line-height:23px; padding-left:20px; } a{ padding:3px 0 3px 40px; display:block; color:#636363; } #my_menu{ width:255px; background:#F7F2E4; height:100%; } div.sdmenu div.collapsed { height: 25px;} div.sdmenu div{ overflow: hidden; }</style></head><body> <div style="float:left" id="my_menu"> <div> <span>菜單一</span> <a href="#">>菜單一子內容</a> <a href="#">>菜單一子內容</a> <a href="#">>菜單一子內容</a> <a href="#">>菜單一子內容</a> <a href="#">>菜單一子內容</a> </div> <div> <span>菜單二</span> <a href="#">>菜單二子內容</a> <a href="#">>菜單二子內容</a> <a href="#">>菜單二子內容</a> </div> <div> <span>菜單三</span> <a href="#">>菜單三子內容</a> <a href="#">>菜單三子內容</a> <a href="#">>菜單三子內容</a> </div> <div> <span>菜單三</span> <a href="#">>菜單三子內容</a> <a href="#">>菜單三子內容</a> <a href="#">>菜單三子內容</a> </div> <div> <span>菜單三</span> <a href="#">>菜單三子內容</a> <a href="#">>菜單三子內容</a> <a href="#">>菜單三子內容</a> </div> <div> <span>菜單x</span> <a href="#">>菜單三子內容</a> <a href="#">>菜單三子內容</a> <a href="#">>菜單三子內容</a> </div> </div></body></html>更多關於JavaScript相關內容感興趣的讀者可查看本站專題：《JavaScript切換特效與技巧總結》、《JavaScript查找算法技巧總結》、《JavaScript動畫特效與技巧匯總》、《JavaScript錯誤與調試技巧總結》、《JavaScript數據結構與算法技巧總結》、《JavaScript遍曆算法與技巧總結》及《JavaScript數學運算用法總結》
希望本文所述對大家JavaScript程序設計有所幫助。