运行效果截图如下：
具体代码如下：
<!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树型菜单</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=https://www.jb51.net/"; } }; 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> <div> <span>菜单一</span> <a href="#">> 菜单一子内容</a> <a href="#">> 菜单一子内容</a> <a href="#">> 菜单一子内容</a> <a href="#">> 菜单一子内容</a> <a href="#">> 菜单一子内容</a> </div> <div> <span>菜单二</span> <a href="#">> 菜单二子内容</a> <a href="#">> 菜单二子内容</a> <a href="#">> 菜单二子内容</a> </div> <div> <span>菜单三</span> <a href="#">> 菜单三子内容</a> <a href="#">> 菜单三子内容</a> <a href="#">> 菜单三子内容</a> </div> <div> <span>菜单三</span> <a href="#">> 菜单三子内容</a> <a href="#">> 菜单三子内容</a> <a href="#">> 菜单三子内容</a> </div> <div> <span>菜单三</span> <a href="#">> 菜单三子内容</a> <a href="#">> 菜单三子内容</a> <a href="#">> 菜单三子内容</a> </div> <div> <span>菜单x</span> <a href="#">> 菜单三子内容</a> <a href="#">> 菜单三子内容</a> <a href="#">> 菜单三子内容</a> </div> </div> </body> </html>