CSS+JavaScript 實作菜單功能--改進版
馬嘉楠 2008-12-08
共同學習,歡迎轉載。轉載請注明位址【http://blog.csdn.net/majianan/archive/2008/12/08/3477388.aspx】,謝謝!
在上一篇《CSS+JavaScript 實作菜單功能》通過一個HTML頁面簡單的實作了菜單功能。但是實際開發當中,如果菜單欄有很多項,頻繁的修改HTML,會很繁瑣,也容易出錯。
改進版本優化了這個問題,通過簡單的Javascript代碼就可以增加菜單。同時使得HTML頁面非常簡潔,隻需要寫2行代碼即可!O(∩_∩)O
1.使用前提,在HTML頁面中引入一個CSS檔案,和一個JavaScript檔案。如下:
- <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
- <HTML>
- <HEAD>
- <TITLE>Menu</TITLE>
- <link type="text/css" rel="stylesheet" href="menu.css">
- </HEAD>
- <BODY>
- <div><script src="menu.js"></script></div>
- </BODY>
- </HTML>
引入CSS檔案:<link type="text/css" rel="stylesheet" href="menu.css"> ,menu.css代碼見後
引入JavaScript檔案:<script src="menu.js"></script>
2.定義菜單代碼如下:
- if (document.getElementById){
- var root = new Root();
- var m1 = new Menu("File","alert(this.innerText);");
- root.add(m1);
- var m11 = new MenuItem("New");
- m1.add(m11);
- m1.add(new MenuItem("Open","alert('open file');"));
- var m12 = new MenuItem("Save");
- m1.add(m12);
- m1.add(new MenuItem("Save As"));
- m1.add(new MenuItem("Close"));
- m1.add(new MenuItem(""));
- var m2 = new Menu("Edit");
- root.add(m2);
- root.toString();
- }
說明:
1) var root = new Root();
root.toString();
固定格式
2)聲明菜單:
var m1 = new Menu("File","alert(this.innerText);");
菜單顯示的名稱為“File”,onclick事件為alert(this.innerText);
root.add(m1);
第一級菜單(即頁面初始顯示的菜單)放到root之下,通過add()方法
var m11 = new MenuItem("New"");
m1.add(m11);
聲明“File”的子菜單“New”
m1.add(new MenuItem("Open","alert('open file');"));
聲明“File”的子菜單“Open”
通過上面的代碼即可完成菜單的添加功能。
代碼檔案:
<1> menu.css
- #menubar {
- font-family:verdana;
- font-size:12px;
- margin:1px;
- }
- #menubar li {
- float:left;
- position:relative;
- text-align:left;
- }
- #menubar li a {
- border-style:none;
- color:black;
- display:block;
- width:150px;
- height:20px;
- line-height:20px;
- padding-left:10px;
- text-decoration:none;
- }
- #menubar .menuMain{
- border-color:#C0C0C0;
- border-width:1px;
- border-style:solid;
- }
- #menubar li a:hover{
- background-color:#efefef;
- text-decoration:underline;
- }
- #menubar li ul{
- background-color:#efefef;
- border-style:none;
- display:none;
- position:absolute;
- top:20px;
- left:-40px;
- margin-top:2px;
- width:150px;
- }
- #menubar li ul li a:hover {
- text-decoration:underline;
- padding-left:20px;
- }
- #menubar li ul li ul {
- display:none;
- position:absolute;
- top:0px;
- left:150px;
- margin-top:0;
- margin-left:0;
- width:150px;
- }
<2>menu.js
- var MenuConfig = {
- defaultText : "Menu Item",
- defaultAction : "javascript:void(0);" ,
- defaultMenuCssStyle : "menuMain"
- };
- var MenuHandler = {
- idCounter : 0,
- idPrefix : "menu-",
- getId : function(){ return this.idPrefix + this.idCounter++ ;},
- insertHTMLBeforeEnd : function(node, sHTML){
- if(node.insertAdjacentHTML != null){
- node.insertAdjacentHTML('BeforeEnd',sHTML);
- return;
- }
- var df; // DocumentFragment
- var r = node.ownerDocument.createRange();
- r.selectNodeContents(node);
- r.collapse(false);
- df = r.createContextualFragment(sHTML);
- node.appendChild(df);
- }
- }
- function displaySubMenu(li){
- var subMenu = li.getElementsByTagName('ul')[0];
- if(subMenu)
- subMenu.style.display = 'block';
- }
- function hideSubMenu(li){
- var subMenu = li.getElementsByTagName('ul')[0];
- if(subMenu)
- subMenu.style.display = 'none';
- }
- function MenuAbstractNode(pText, pAction){
- this.text = pText || MenuConfig.defaultText;
- this.action = pAction || MenuConfig.defaultAction;
- this.id = MenuHandler.getId();
- this.childNodes = [];
- }
- MenuAbstractNode.prototype.add = function(node){
- this.childNodes[this.childNodes.length] = node;
- }
- MenuAbstractNode.prototype.toString = function(){
- var str = "<li id=/"" + this.id + "/" οnmοuseοver=/"displaySubMenu(this)/" οnmοuseοut=/"hideSubMenu(this)/"><a href=/"#/"";
- if(this.type=="Menu"){
- str = str + " class=/"" + this.cssStyle + "/"";
- }
- str = str + " οnclick=/""+this.action+"/">"+this.text+"</a>";
- var sb = [];
- for (var i = 0; i < this.childNodes.length; i++) {
- sb[i] = this.childNodes[i].toString();
- }
- if(sb.length>0){
- str = str + "<ul>" + sb.join("") + "</ul>"
- }
- return str + "</li>" ;
- }
- function Menu(pText, pAction,pCssStyle){
- this.base = MenuAbstractNode;
- this.base(pText,pAction);
- this.type = "Menu";
- this.cssStyle = pCssStyle || MenuConfig.defaultMenuCssStyle;
- }
- Menu.prototype = new MenuAbstractNode;
- function MenuItem(pText, pAction){
- this.base = MenuAbstractNode;
- this.base(pText,pAction);
- this.type = "MenuItem";
- }
- MenuItem.prototype = new MenuAbstractNode;
- function Root(){
- this.id = "menubar";
- this.childNodes=[];
- }
- Root.prototype = new MenuAbstractNode;
- Root.prototype.toString = function(){
- document.write("<div id='menu'><ul id=/""+root.id+"/"> </ul> </div>");
- for(var i=0; i<this.childNodes.length; i++){
- MenuHandler.insertHTMLBeforeEnd(document.getElementById(root.id), this.childNodes[i].toString());
- }
- }
- if (document.getElementById){
- var root = new Root();
- var m1 = new Menu("File","alert(this.innerText);");
- root.add(m1);
- var m11 = new MenuItem("New","alert(this.innerText);");
- m1.add(m11);
- m1.add(new MenuItem("Open","alert('open file');"));
- var m12 = new MenuItem("Save");
- m1.add(m12);
- m1.add(new MenuItem("Save As"));
- m1.add(new MenuItem("Close"));
- m1.add(new MenuItem(""));
- var m2 = new Menu("Edit");
- root.add(m2);
- var m22 = new MenuItem("Select All");
- m2.add(m22);
- m2.add(new MenuItem("Cut"));
- m2.add(new MenuItem("Copy"));
- m2.add(new MenuItem("paste"));
- var m3 = new Menu("View");
- var m33 = new MenuItem("View List");
- m33.add(new MenuItem("Function List"));
- m3.add(m33);
- m3.add(new MenuItem("Tool Bar"));
- root.add(m3);
- root.toString();
- }