Javascript菜单冲突

我遇到了Javascript冲突。我有一个垂直的javascript左导航菜单和一个水平的javascript时区菜单。这两个都可以使用代码，但当我在同一页面中调用它们时，菜单树不起作用。如果我取出

标签，菜单工作正常，但时区被否定<代码>问题

html

---

他们都在设置window.onload

快速修复方法是从以下内容更改timezone.js：

onload=function(){
var root = document.getElementById('zonediv');
...

对此

var oldOnload = window.onload;
window.onload = function()
{
    if (oldOnload)
        oldOnload();

    var root = document.getElementById('zonediv');
    ...

var wd=['Sun','Mon','Tue','Wed','Thu','Fri','Sat'];
var D=[['Bucharest',120,60],['Madrid',60,60],['New York',-300,60],['Nairobi',180,0]]//city,standard time zone(minutes), DST(minutes)

//add in the array your cities,STZ, DST
function calc(){
var spans=document.getElementById('zonediv').getElementsByTagName('span')
for(var i=0;i<D.length;i++){
var t=new Date();
t.setTime(t.getTime()+(t.getTimezoneOffset()*60000)+((D[i][1]+D[i][2])*60000));//the zone's time
var Dy=t.getFullYear();
var Dd=t.getDate()<10?'0'+t.getDate():t.getDate();
var Dm=t.getMonth()<10?'0'+(t.getMonth()+1):t.getMonth()+1;
var Dh=t.getHours()<10?'0'+t.getHours():t.getHours(); 
var Di=t.getMinutes()<10?'0'+t.getMinutes():t.getMinutes();
var Ds=t.getSeconds()<10?'0'+t.getSeconds():t.getSeconds();
var Dz=wd[t.getDay()];
spans[i].firstChild.data=Dh+':'+Di+':'+Ds;
}
setTimeout('calc()',1000)
}
onload=function(){
var root = document.getElementById('zonediv');
for(var i=0;i<D.length;i++){
root.appendChild(document.createTextNode(D[i][0]+' '))
var sp= document.createElement('span');
sp.appendChild(document.createTextNode('span'));
root.appendChild(sp);root.appendChild(document.createTextNode(' | '));
}
calc();
}

/* Left Navigation Menu */


DIV.left {
    background-image: url('images/LeftNav.gif'); WIDTH: 190px; HEIGHT: 100%
}
TD.top {
    FONT-WEIGHT: bold; FONT-SIZE: 13px; COLOR: #D5D7C0; TEXT-INDENT: 10px; LINE-HEIGHT: 26px; font-family: Verdana;
background-color:#3D3D3D;
/*background-image: url('images/LeftNav.gif');*/
}
TD.section {
    PADDING-RIGHT: 12px; PADDING-LEFT: 12px; PADDING-BOTTOM: 6px; PADDING-TOP: 6px
}
.bar-menu {
    moz-user-select: none
}
.bar-menu .box1 {
    PADDING-LEFT: 19px; BACKGROUND: url(images/tree-node.gif) no-repeat; CURSOR: default
}
.bar-menu .box1-open {
    PADDING-LEFT: 19px; BACKGROUND: url(images/tree-node-open.gif) no-repeat; CURSOR: default
}
.bar-menu .box1 {
    font-family: Verdana;
    font-size: 13px;
    color:#3D3D3D;

}



.bar-menu .box1-open {
    font-family: Verdana;
    font-size: 11px;
    color:#3D3D3D;
    
    }
UNKNOWN {
    FONT-SIZE: 12px; PADDING-BOTTOM: 1px; COLOR: #000000; LINE-HEIGHT: 16px; FONT-FAMILY: arial
}
 HTML .bar-menu .box1 {
    FONT-SIZE: 12px; COLOR: #000000; FONT-FAMILY: arial; HEIGHT: 16px
}
 HTML .bar-menu .box1-open {
    FONT-SIZE: 12px; COLOR: #000000; FONT-FAMILY: arial; HEIGHT: 16px
}
.bar-menu .section {
    DISPLAY: none; FONT-SIZE: 12px; LINE-HEIGHT: 16px; FONT-FAMILY: arial
}
.bar-menu .section A {
    COLOR: #000000; WHITE-SPACE: nowrap; TEXT-DECORATION: none
}
.bar-menu .section A:hover {
    COLOR: #0000ff; WHITE-SPACE: nowrap; TEXT-DECORATION: none
}
.bar-menu .box2 {
    PADDING-LEFT: 19px; BACKGROUND: url(images/tree-leaf.gif) no-repeat
}
.bar-menu .box2-last {
    PADDING-LEFT: 19px; BACKGROUND: url(images/tree-leaf-last.gif) no-repeat
}

onload=function(){
var root = document.getElementById('zonediv');
...

var oldOnload = window.onload;
window.onload = function()
{
    if (oldOnload)
        oldOnload();

    var root = document.getElementById('zonediv');
    ...