一段用js实现的下拉列表代码。。

<script language="JavaScript" type="text/JavaScript">
<!--
function MM_jumpMenu(targ,selObj,restore){ //v3.0
  eval(targ+".location='"+selObj.options[selObj.selectedIndex].value+"'");
  if (restore) selObj.selectedIndex=0;
}
//-->

<script language=javascript>
<!--
var old_menu = '';
var old_cell = '';
function menuclick( submenu ,cellbar)
{
if( old_menu != submenu ){
if( old_menu !='' ){
old_menu.style.display = 'none';
old_cell.src= 'plus.gif';
}
submenu.style.display = 'block';
cellbar.src = 'plus.gif';
old_menu = submenu;
old_cell = cellbar;

}else{
submenu.style.display = 'none';
cellbar.src= 'plus.gif';
old_menu = '';
old_cell = '';
}
}
function RemoteWindow( url )
{
window.open( url, 'PreviewWin1','width=740,height=450,resizable=yes,scrollbars=yes,status=0,location=no')
}
function RemoteWindow2( url )
{
window.open( url, 'PreviewWin2','width=700,height=300,resizable=yes,scrollbars=yes,status=0,fullscreen=yes')
}
function RemoteWindow3( url )
{
window.open( url, 'sub','width=740,height=300,resizable=yes,scrollbars=yes,status=0,location=no')
}

function MM_preloadImages(){//v3.0
var d=document; if(d.images){if(!d.MM_p) d.MM_p=new Array();
var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
if (a[i].indexOf("#")!=0){d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_findObj(n, d){//v3.0
var p,i,x; if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length){
d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document); return x;
}

function MM_nbGroup(event, grpName){//v3.0
var i,img,nbArr,args=MM_nbGroup.arguments;
if (event == "init" && args.length > 2){
if ((img = MM_findObj(args[2])) != null && !img.MM_init){
img.MM_init = true; img.MM_up = args[3]; img.MM_dn = img.src;
if ((nbArr = document[grpName]) == null) nbArr = document[grpName] = new Array();
nbArr[nbArr.length] = img;
for (i=4; i < args.length-1; i+=2) if ((img = MM_findObj(args[i])) != null){
if (!img.MM_up) img.MM_up = img.src;
img.src = img.MM_dn = args[i+1];
nbArr[nbArr.length] = img;
}}
}else if (event == "over"){
document.MM_nbOver = nbArr = new Array();
for (i=1; i < args.length-1; i+=3) if ((img = MM_findObj(args[i])) != null){
if (!img.MM_up) img.MM_up = img.src;
img.src = (img.MM_dn && args[i+2]) ? args[i+2] : args[i+1];
nbArr[nbArr.length] = img;
}
}else if (event == "out" ){
for (i=0; i < document.MM_nbOver.length; i++){
img = document.MM_nbOver[i]; img.src = (img.MM_dn) ? img.MM_dn : img.MM_up;}
}else if (event == "down"){
if ((nbArr = document[grpName]) != null)
for (i=0; i < nbArr.length; i++){img=nbArr[i]; img.src = img.MM_up; img.MM_dn = 0;}
document[grpName] = nbArr = new Array();
for (i=2; i < args.length-1; i+=2) if ((img = MM_findObj(args[i])) != null){
if (!img.MM_up) img.MM_up = img.src;
img.src = img.MM_dn = args[i+1];
nbArr[nbArr.length] = img;
}}
}
//-->
</script>