下拉菜单被表单挡住的几种解决方法

当层遇到下拉框时总是挡不了select框?其实这是IE的BUG,其它的浏览器没有这个问题,对于这个问题论坛里不少提出,在这里提供我的几种方法,各有各的好处,有错,有好的意见者提出,谢谢.

1.最直接的方法:隐藏下拉框.

下面提供的是一个比较通用的一组函数:

test.htm

------------

程序代码：

<script>
var HideElementTemp = new Array();
//点击菜单时，调用此的函数,菜单对象
function cal_hideElementAll(obj){ 
cal_HideElement("IMG",obj);
cal_HideElement("SELECT",obj);
cal_HideElement("OBJECT",obj);
cal_HideElement("IFRAME",obj);
}
function cal_HideElement(strElementTagName,obj){
try{
var showDivElement = obj;
var calendarDiv = obj;
var intDivLeft = cal_GetOffsetLeft(showDivElement);
var intDivTop = cal_GetOffsetTop(showDivElement);//+showDivElement.offsetHeight;
//HideElementTemp=new Array()
for(i=0;i<window.document.all.tags(strElementTagName).length; i++){
var objTemp = window.document.all.tags(strElementTagName)[i];
if(!objTemp||!objTemp.offsetParent)
continue;
var intObjLeft=cal_GetOffsetLeft(objTemp);
var intObjTop=cal_GetOffsetTop(objTemp);
if(((intObjLeft+objTemp.clientWidth)>intDivLeft)&&
(intObjLeft<intDivLeft+calendarDiv.style.posWidth)&&
(intObjTop+objTemp.clientHeight>intDivTop)&&
(intObjTop<intDivTop+calendarDiv.style.posHeight)){
//var intTempIndex=HideElementTemp.length;//已经有的长度
//save elementTagName is stutas
//HideElementTemp[intTempIndex]=new Array(objTemp,objTemp.style.visibility);
HideElementTemp[HideElementTemp.length]=objTemp
objTemp.style.visibility="hidden";
}
}
}catch(e){alert(e.message)
}
}

function cal_ShowElement(){
var i;
for(i=0;i<HideElementTemp.length; i++){
var objTemp = HideElementTemp[i]
if(!objTemp||!objTemp.offsetParent)
continue;
objTemp.style.visibility=''
}
HideElementTemp=new Array();
}
function cal_GetOffsetLeft(src){
var set=0;
if(src && src.name!="divMain"){
if (src.offsetParent){
set+=src.offsetLeft+cal_GetOffsetLeft(src.offsetParent);
}
if(src.tagName.toUpperCase()!="BODY"){
var x=parseInt(src.scrollLeft,10);
if(!isNaN(x))
set-=x;
}
}
return set;
}

function cal_GetOffsetTop(src){
var set=0;
if(src && src.name!="divMain"){
if (src.offsetParent){
set+=src.offsetTop+cal_GetOffsetTop(src.offsetParent);
}
if(src.tagName.toUpperCase()!="BODY"){
var y=parseInt(src.scrollTop,10);
if(!isNaN(y))
set-=y;
}
}
return set;
}

</script>
<select></select>
<select></select>
<div style="position:absolute;left:0;top:0;width:100;height:100;background-color:red" onclick="cal_hideElementAll(this)">
点击让select隐藏
</div>
<br/><br/><br/><br/><br/><br/>
<input type="button" value="点击让select显示" onclick="cal_ShowElement()">

以上这种方法,如果对于select框数目少,相对固定的话,直接用obj.style.visibility="hidden"这样进行隐藏是更直接的.

2.Object对象的优先度较高,可以挡住select框

程序代码：

<OBJECT id=aa style="display:none;z-index:1000; position:absolute; top:0; left:0; width:152; height: 200;" type="text/x-scriptlet" data="about:<body><div style='position:absolute;left:0;top:0;width:152;height:200;font:14;color:white;background:black;border:1 solid black'>test</div>"></OBJECT>
<select><option>hellohellohellohello</select><button onclick=aa.style.display=aa.style.display=="none"?"":"none">test</button>

这种方法虽然也简单,但对复杂的层是来说还不是好的解决方法

3.用iframe作载体

以下是一简单的例子:

-----------

程序代码：

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>简单菜单</title>
<!--
提供定位函数，用iframe作载体，不会被select挡住
By Fason(2003-5-21)
-->
<style id=s>
#div1{
position:absolute;
z-index:100;
width:100;
height:130;
background-color:#d2e8ff;
border:1 solid black;
}
div{cursor:hand;font-size:12px;}
a{text-decoration:none;color:red;font-size:12px}
</style>
</head>
<body>
<script>
function window.onload(){
var shtml=div1.innerHTML;
var ifm=document.createElement("<iframe frameborder=0 marginheight=0 marginwidth=0 hspace=0 vspace=0 scrolling=no></iframe>")
ifm.style.width=div1.offsetWidth
ifm.style.height=div1.offsetHeight
ifm.name=ifm.uniqueID
div1.innerHTML=""
div1.appendChild(ifm)
window.frames[ifm.name].document.write(s.outerHTML+"<body leftmargin=0 topmargin=0>"+shtml+"</body>")
}

function show(){
with(document.all.img1){
x=offsetLeft;
y=offsetTop;
objParent=offsetParent;
while(objParent.tagName.toUpperCase()!= "BODY"){
x+=objParent.offsetLeft;
y+=objParent.offsetTop;
objParent = objParent.offsetParent;
}
y+=offsetHeight-1
}
with(document.all.div1.style){
pixelLeft=x
pixelTop=y
visibility=''
}
}
function hide(){
document.all.div1.style.visibility='hidden'
}
</script>
<img id=img1 onmouseover="show()" onmouseout="hide()" src="ie.gif"><br/><select></select>
<div id=div1 onmouseover="style.visibility=''" onmouseout="style.visibility='hidden'" style="visibility:hidden;">
<div href="http://www.csdn.net" onmouseover="style.backgroundColor='highlight'" onmouseout="style.backgroundColor=''" onclick="window.open(href)">中国程序员</div>
<div href="http://www.sohu.com" onmouseover="style.backgroundColor='highlight'" onmouseout="style.backgroundColor=''" onclick="window.open(href)">sohu</div>
</div>
</body>
</html>

更多的下拉菜单被表单挡住的几种解决方法请到论坛查看: http://BBS.TC711.COM

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