javascript|xml|菜单|下拉　　一、简单说明

该菜单最大的优点是可以跨过网页上任何标签，甚至是框架，（一般的菜单会被select,object,flash等挡住）所以如果你有这方面的需要，那么这个菜单是个很好的选择。

总体而言，它有如下特性：

（1）菜单的样式和数据都是通过xml配置

（2）菜单的样式可以随心所欲修改，如：

<base>
<background-color>#DDDDDD</background-color>
<background-image>url(menu_bg.jpg)</background-image>
<font-size>10pt</font-size>
<color>#000099</color>
<width>100%</width>
<height>32</height>
<text-align>center</text-align>
<cursor>default</cursor>
</base>

只要节点名称符合各自标签(table,tr,td之一)的style attribute即可。

（3）主菜单项之间可以设置分割图片，子菜单项可以设置分割线的样式。

（4）所有图片都由css控制，避免路径问题。

（5）可以设置虚拟目录的别名，为菜单链接使用绝对路径带来方便，如：

<context>
<path>hdsa</path>
</context>

设置该值后，用户只需根据文件的目录结构写好菜单，而不必担心虚拟目录的问题。

由于菜单使用了window.createPopup()，所以它被限制在IE5.5以上，而且子菜单如果是新开窗口，会被拦截。

注：用window.createPopup()制作菜单受到过前人的启发

设置该值后，用户只需根据文件的目录结构写好菜单，而不必担心虚拟目录的问题。

由于菜单使用了window.createPopup()，所以它被限制在IE5.5以上，而且子菜单如果是新开窗口，会被拦截。

注：用window.createPopup()制作菜单受到过前人的启发
=====================================================================

二、实现的两个脚本可以写在一个文件中：

（1）处理Popup窗口的脚本

//------------------ 下面一些函数用来处理弹出窗口　------------------ //
var pops = new Array(); // 用来存储Popup窗口家族的数组
function CreatePopup(degree)
{
if (degree < 0)　　// 层数不能小于0
return null;
if (pops[degree] != null) //如果已经存在则不需创建
return pops[degree];

if (degree == 0)
pops[0] = window.createPopup(); //创建最顶层Popup窗口
else{
if (pops[degree - 1] == null)
pops[degree - 1] = CreatePopup(degree - 1)　　//递归回溯从第一层开始创建
pops[degree] = pops[degree - 1].document.parentWindow.createPopup(); //从父Popup窗口创建子Popup窗口
}
pops[degree].document.body.setAttribute("degree", degree);
return pops[degree];
}

CreatePopup(1); //创建一个2层的Popup家族

var oPopup = pops[0];
var timer = null;

/**
*显示一级子菜单
*param objShow - 显示子菜单的对象
*param strGetID - 存储显示内容的标签id
*/
function showSubMenu1(objShow,strGetID) {
clearTimer();
endHideSubMenu();
var objGet = eval(document.getElementById(strGetID));

pops[1].hide();
pops[0].document.body.innerHTML = objGet.innerHTML;
pops[0].show(0,0,1,1,objShow);
var intWidth = pops[0].document.body.scrollWidth;
var intHeight = pops[0].document.body.scrollHeight;
pops[0].hide();
pops[0].show(10,objShow.offsetHeight-2,intWidth,intHeight,objShow);
}

/**
*显示二级菜单
*param strGetID - 存储显示内容的标签id
*param objTr - 显示子菜单的tr对象
*/
function showSubMenu2(strGetID,objTr) {
clearTimer();
endHideSubMenu();
var objGet = eval(document.getElementById(strGetID));
pops[1].document.body.innerHTML = objGet.innerHTML;
pops[1].show(0,0,1,1,pops[0].document.body);
var intWidth = pops[1].document.body.scrollWidth;
var intHeight = pops[1].document.body.scrollHeight;
pops[1].hide();
pops[1].show(objTr.offsetWidth - 2,-2, intWidth, intHeight, objTr);

}

//隐藏一级子菜单
function hideSubMenu1(){
//pops[0].hide();
window.setTimeout("pops[0].hide()", 1000);
}

//隐藏二级子菜单
function hideSubMenu2()
{
//clearTimer();
//timer = window.setTimeout("pops[1].hide()", 1000);
pops[1].hide();
}

//隐藏所有下拉菜单
function hideSubMenu()
{
if(pops[0] != null)pops[0].hide();
if(pops[1] != null)pops[1].hide();
}

function clearTimer()
{
if (timer != null)
window.clearTimeout(timer)
timer = null;
//alert("OK");
}

（2）读取分析xml数据文件，打印菜单的脚本

//位置信息
var m_strTitle = "您的位置->";

// -------- 主菜单样式相关定义 ---------//

//定义主菜单样式
var m_strMainMenuStyle = "";
//主菜单项的样式attribute
var m_strMainMenuItemStyle = "";
//主菜单项样式Property
var m_strMMItemProBase = {};
//主菜单项鼠标悬停样式Property
var m_strMMItemProMOver = {};
//菜单项与项之间的分割图片
var m_strMMItemSplitImg;

// -------- 子菜单样式相关定义 ---------//

//定义子菜单样式
var m_strSubMenuStyle = "";
//子菜单项的样式attribute
var m_strSubMenuItemStyle = "";
//子菜单项样式Property
var m_strSMItemProBase = {};
//子菜单项鼠标悬停样式Property
var m_strSMItemProMOver = {};
//子菜单项下边框样式(作为分割线)
var m_strSMItemBorderB = "";

//定义虚拟目录路径
var m_strContextPath = "";

//菜单xml数据文件对象
var m_doc;

//主菜单集合
var m_objMMList;

var STR_POS_FRONT = "您的位置：";

//loadMenu("main_menu.xml");
/**
*加载菜单
*param strXMLPath - XML数据文件所在路径及文件名
*/
function loadMenu(strXMLFile) {
m_doc = new ActiveXObject("MSXML2.DOMDocument.3.0");
m_doc.async = false;
m_doc.load(strXMLFile);

getMainMenuStyle();
getSubMenuStyle();

//得到主菜单集合
m_objMMList = m_doc.selectSingleNode("//popmenu/menus").childNodes;

//得到虚拟目录
if( m_doc.selectSingleNode("//popmenu/context/path") ) {
m_strContextPath = m_doc.selectSingleNode("//popmenu/context/path").text;
}

//输出主菜单
printMainMenu();
//输出一级子菜单
printSubMenu();

}

/**
*鼠标移入移出主菜单样式的改变
*param obj - 改变样式的对象
*param bolChg - 是否改变样式
*/
function chgMainMenuStyle(obj,bolChg)
{
if ( bolChg ) {//鼠标悬停改变颜色
for( var pro in m_strMMItemProMOver ) {
obj.style[pro] = m_strMMItemProMOver[pro];
}
} else {//鼠标移出
obj.style.border = "0";
for( var pro in m_strMMItemProBase ) {
obj.style[pro] = m_strMMItemProBase[pro];
}
}
}//end function chgMainMenuStyle(obj,i)

/**
*鼠标移入移出子菜单样式的改变
*param obj - 改变样式的对象
*param bolChg - 是否改变样式
*/
function chgSubMenuStyle(obj,bolChg) {
if ( bolChg ) {//鼠标悬停改变颜色
for( var pro in m_strSMItemProMOver ) {
obj.style[pro] = m_strSMItemProMOver[pro];
}
} else {//鼠标移出
for( var pro in m_strSMItemProBase ) {
obj.style[pro] = m_strSMItemProBase[pro];
}
}
}//end function chgSubMenuStyle(obj,i)

/**
*构造节点样式
*param strPath 节点路径
*/
function getNodeStyle(strPath) {
var strStyle = "";
if( m_doc.selectSingleNode(strPath) ) {
var nodeList = m_doc.selectSingleNode(strPath).childNodes;
for( var i = 0;i < nodeList.length;i ++ ) {
var nodeName = nodeList[i].nodeName;
var nodeText = nodeList[i].text;
strStyle += nodeName.toLowerCase() + ":" + nodeText + ";";
}
}
return strStyle;
}
/**
*构造节点Style Property
*/
function getNodeProperty(strPath) {
var arrProperty = {};
if( m_doc.selectSingleNode(strPath) ) {
var nodeList = m_doc.selectSingleNode(strPath).childNodes;
for( var i = 0;i < nodeList.length;i ++ ) {
var nodeName = nodeList[i].nodeName;
nodeName = nodeName.toLowerCase();
var nodeText = nodeList[i].text;
//由attribute到property的转变。如background-color -> backgroundColor
var aName = nodeName.split("-");
var strProperty = aName[0];
for( var j = 1;j < aName.length;j ++ ) {
strProperty += aName[j].substring(0,1).toUpperCase() + aName[j].substr(1);
}
arrProperty[strProperty] = nodeText;
}
}
return arrProperty;
}

/**
*得到主菜单样式
*/
function getMainMenuStyle() {

//得到主菜单样式
m_strMainMenuStyle = getNodeStyle("//popmenu/style/main-menu/base");
//得到主菜单项样式
m_strMainMenuItemStyle = getNodeStyle("//popmenu/style/main-menu/menu-item/base");

//主菜单项的property
m_strMMItemProBase = getNodeProperty("//popmenu/style/main-menu/menu-item/base");

//得到鼠标悬停时主菜单项各property改变
m_strMMItemProMOver = getNodeProperty("//popmenu/style/main-menu/menu-item/mouse-over");

//得到菜单项与项之间的分割图片
if( m_doc.selectSingleNode("//popmenu/style/main-menu/menu-item/split-image") ) {
var node = m_doc.selectSingleNode("//popmenu/style/main-menu/menu-item/split-image");
m_strMMItemSplitImg = "background-image:" + node.text + ";";
m_strMMItemSplitImg += "background-repeat:no-repeat;background-position:center center;";
}

}//end function getMainMenuStyle()

/**
*得到主菜单样式
*/
function getSubMenuStyle() {

//得到子菜单样式
m_strSubMenuStyle = getNodeStyle("//popmenu/style/sub-menu/base");
//得到子菜单项样式
m_strSubMenuItemStyle = getNodeStyle("//popmenu/style/sub-menu/menu-item/base");

//子菜单项的property
m_strSMItemProBase = getNodeProperty("//popmenu/style/sub-menu/menu-item/base");

//得到鼠标悬停时子菜单项各property改变
m_strSMItemProMOver = getNodeProperty("//popmenu/style/sub-menu/menu-item/mouse-over");

//得到子菜单项下边框样式(作为分割线)
if( m_doc.selectSingleNode("//popmenu/style/sub-menu/menu-item/split-line") ) {
var node = m_doc.selectSingleNode("//popmenu/style/sub-menu/menu-item/split-line");
m_strSMItemBorderB = "border-bottom:" + node.text + ";";
}

}//end function getSubMenuStyle()

var m_bolFirst = true;//是否首次响应菜单
document.onclick = function(){
m_bolFirst = true;
//alert(parent.frames[0]);
}
top.document.onclick = function(){
m_bolFirst = true;
}

/**
*展开各个主菜单
*param objTd - 主菜单所在td
*param strSubMenuID - 对应子菜单的id
*param bolExistSubMenu - 是否存在子菜单
*/
function spreadMainMenu(objTd,strSubMenuID,bolExistSubMenu){

var strEvent = event.type.toLowerCase();

if( !pops[0].isOpen && strEvent == "mouseover" && m_bolFirst){
return;
}
if( pops[0].isOpen && strEvent == "click"){
return;
}
chgMainMenuStyle(objTd,true);
endHideSubMenu();
if( bolExistSubMenu ){
//如果有子菜单
showSubMenu1(objTd,strSubMenuID);
} else　{
//hideSubMenu();
//m_bolFirst = false;//已不是第一次响应菜单
}
}

//打印主菜单
function printMainMenu()
{
var divStyle = "width:100%;";
var strHtml = "";
strHtml = "<div + divStyle + "'>";
strHtml += "<table cellpadding='3'><tr>";
//如果用户设置了分割图片则输出
if( m_strMMItemSplitImg && m_strMMItemSplitImg != "" ){
strHtml += "<td + m_strMMItemSplitImg + "' width=2></td>";
}
var intMenuWidth = 0;

for ( var i = 0 ; i< m_objMMList.length ; i ++ )
{
var menuNode = m_objMMList[i];
var attList = menuNode.attributes;
var menuText = attList.getNamedItem("text").text;
var menuHref = attList.getNamedItem("href").text;
var menuTarget = "";
if( attList.getNamedItem("target") )
menuTarget = attList.getNamedItem("target").text;
else
menuTarget = "_self";

var intMenuWidth;
if( attList.getNamedItem("width") )
intMenuWidth = attList.getNamedItem("width").text;

var strSubMenuID = "sm" + i;
var strMouseOverEvent = "";
var strClickEvent = "";
//如果有子拉菜单，则显示
if ( menuNode.hasChildNodes() ){
strMouseOverEvent = "chgMainMenuStyle(this,true);spreadMainMenu(this,\"" + strSubMenuID + "\",true);";
strClickEvent = strMouseOverEvent;
}else{
strMouseOverEvent = "chgMainMenuStyle(this,true);";
strClickEvent = "onClickEvent('" + menuHref + "','" + menuTarget + "','" + menuText + "');";
}

strHtml += "<td　width=" + intMenuWidth + " + m_strMainMenuItemStyle + "'　id=mm" + i +
" " +
" >" + menuText+"</td>";

//如果用户设置了分割图片则输出
if( m_strMMItemSplitImg && m_strMMItemSplitImg != "" ){
strHtml += "<td + m_strMMItemSplitImg + "' width='2'></td>";
}
}
strHtml += "<td></td>";
strHtml += "</tr>";
strHtml += "</table>";
strHtml += "</div>";

document.write(strHtml);
}//end printMainMenu()

//打印一级子菜单
function printSubMenu() {
for ( var i = 0 ; i< m_objMMList.length ; i ++ ) {
menuNode = m_objMMList[i];
//如果没有子菜单，执行下一个循环
if ( !menuNode.hasChildNodes() ){
continue;
}

//得到主菜单下的子菜单集合
var objSMList = menuNode.childNodes;
var intSubMenuLen = objSMList.length;

//每个主菜单对应的子菜单id
var strSubMenuID = "sm" + i;
//arrMenuID.push(strSubMenuID);

var strSubMenuHtml = "<div id='" + strSubMenuID + "'>" +
" <table　cellspacing='0' cellpadding='4' + m_strSubMenuStyle + "'>";

for ( var j = 0;j < intSubMenuLen;j ++ ) {
var objSubMenu = objSMList[j];
var attList = objSubMenu.attributes;
var menuText = attList.getNamedItem("text").text;
var menuHref = attList.getNamedItem("href").text;
var menuTarget = "";
if( attList.getNamedItem("target") )
menuTarget = attList.getNamedItem("target").text;
else
menuTarget = "_self";

//如果有三级子菜单，则需要箭头标识
var strRightRow = " ";
//二级子菜单id
var strSubMenu2ID = strSubMenuID + "_sm" + j;
//鼠标悬停和移出时一级子菜单的响应
var strMouseOverEvent = "parent.chgSubMenuStyle(this,true);parent.endHideSubMenu();";
var strMouseOutEvent = " parent.chgSubMenuStyle(this,false);parent.beginHideSubMenu();";

//位置信息显示
var strPosition = STR_POS_FRONT +　m_objMMList[i].attributes.getNamedItem("text").text +　"->"
+ menuText;
//alert(strPosition);
if ( objSubMenu.hasChildNodes() ) {
//打印其二级子菜单
printSubMenu2(objSubMenu,strSubMenu2ID,strPosition);

strMouseOverEvent += "parent.showSubMenu2(\"" + strSubMenu2ID + "\",this);";
//strMouseOutEvent += "parent.beginHideSubMenu();";
strRightRow = "<font = "";
} else {
//strMouseOverEvent += "parent.endHideSubMenu();";
strMouseOverEvent += "parent.hideSubMenu2();";
}
var strOnClickEvent = "javascript:parent.onClickEvent('" + menuHref + "','" + menuTarget + "','" + strPosition + "');"
strSubMenuHtml += "<tr + m_strSubMenuItemStyle + "' " +
" onmouseover='" + strMouseOverEvent + "' " +
" onmouseout='" + strMouseOutEvent + "' " +
" onclick= " + strOnClickEvent + " " +
" > <td width='3' nowrap + m_strSMItemBorderB + "'> </td>"+
"　　<td nowrap + m_strSMItemBorderB + "'>" + menuText + "</td>"+
"　　<td width='10' align='right' nowrap + m_strSMItemBorderB + "'>" + strRightRow + "</td>" +
"</tr>";
//alert(objSubMenu.text.length);

}//end for 子菜单个数循环

strSubMenuHtml += "</table></div>";

document.write(strSubMenuHtml);

}//end for 主菜单个数循环
}//end function printSubMenu()

/**打印二级子菜单
*objSubMenu : 一级子菜单对象
*strSubMenu2ID ：将要打印的二级菜单的id
*strPosition：主菜单和一级子菜单文本描述
*/
function printSubMenu2(objSubMenu,strSubMenu2ID,strPosition)
{
//arrMenuID.push(strSubMenu2ID);
var objSMList = objSubMenu.childNodes;
var intSubMenu2Len = objSMList.length;

var strSubMenu2Html = "<div + strSubMenu2ID + "'>" +
" <table　cellspacing='0' cellpadding='4' + m_strSubMenuStyle + "'>";

for ( var i = 0; i< intSubMenu2Len;i ++ )
{
var objSubMenu2 = objSMList[i];
var attList = objSubMenu2.attributes;
var menuText = attList.getNamedItem("text").text;
var menuHref = attList.getNamedItem("href").text;

var menuTarget = "";
if( attList.getNamedItem("target") )
menuTarget = attList.getNamedItem("target").text;
else
menuTarget = "_self";

var strPostion2 = strPosition + "->" + menuText;

strSubMenu2Html += "<tr + m_strSubMenuItemStyle + "' " +
" onmouseover='parent.parent.chgSubMenuStyle(this,true);" +
" parent.parent.endHideSubMenu(); ' " +
" " +
" onclick=javascript:parent.parent.onClickEvent('" + menuHref + "','" + menuTarget + "','" + strPostion2 + "'); " +
" > <td width='3' nowrap + m_strSMItemBorderB + "'> </td>"+
"　　<td nowrap + m_strSMItemBorderB + "'>" + menuText + "</td>"+
"　　<td width='3' nowrap + m_strSMItemBorderB + "'> </td>" +
"</tr>";
}
strSubMenu2Html += "</table></div>";

document.write(strSubMenu2Html);

}//end function printSubMenu2

/**
*打开链接，所有菜单的链接都是通过这个函数来打开。并显示位置信息
*param strUrl - 打开链接的地址
*param strTarget - 打开链接的target。如_self,_blank等
*param strViewText - 位置信息
*/
function onClickEvent(strUrl,strTarget,strViewText)
{
m_bolFirst = true;//以后响应菜单时变为为第一次响应
//document.all.selected_menu.innerText = strViewText;

m_strTitle = "";
var arrText = strViewText.split("->");
if ( arrText.length >0 )
m_strTitle = arrText[0];
for (var i = 1; i < arrText.length ; i ++ )
{
m_strTitle += "－" + arrText[i];
}
m_strTitle = m_strTitle.substring(STR_POS_FRONT.length);
//隐藏下拉菜单
hideSubMenu();
//显示title
if (m_strTitle != "")
{
//parent.document.title = m_strTitle;
}

if ( strUrl == "#" )
return;

//如果url是一个javascript字符串则直接执行之
if(strUrl.toLowerCase().indexOf("javascript") != -1) {
executeScript(strUrl);
return;
}

strUrl = m_strContextPath + strUrl;//地址应加上虚拟目录

window.open(strUrl,strTarget);
}
//执行一个javascript字符串
function executeScript(strScript)
{
//第一个eval得到该字符串表示的变量，第二个eval则执行变量里的脚本
eval(strScript);
}