本文實例講述了JavaScript實現(xiàn)彈出DIV層同時頁面背景漸變成半透明效果。分享給大家供大家參考，具體如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>JavaScript彈出DIV層，頁面背景漸變成半透明</title>
<style>
html,body{font-size:12px;margin:0px;height:100%;}
.mesWindow{border:#666 1px solid;background:#fff;}
.mesWindowTop{border-bottom:#eee 1px solid;margin-left:4px;padding:3px;font-weight:bold;text-align:left;font-size:12px;}
.mesWindowContent{margin:4px;font-size:12px;}
.mesWindow .close{height:15px;width:28px;border:none;cursor:pointer;text-decoration:underline;background:#fff}
</style>
<script>
var isIe=(document.all)?true:false;
//設(shè)置select的可見狀態(tài)
function setSelectState(state)
{
var objl=document.getElementsByTagName('select');
for(var i=0;i<objl.length;i++)
{
objl[i].style.visibility=state;
}
}
function mousePosition(ev)
{
if(ev.pageX || ev.pageY)
{
return {x:ev.pageX, y:ev.pageY};
}
return {
x:ev.clientX + document.body.scrollLeft - document.body.clientLeft,y:ev.clientY + document.body.scrollTop - document.body.clientTop
};
}
//彈出方法
function showMessageBox(wTitle,content,pos,wWidth)
{
closeWindow();
var bWidth=parseInt(document.documentElement.scrollWidth);
var bHeight=parseInt(document.documentElement.scrollHeight);
if(isIe){
setSelectState('hidden');}
var back=document.createElement("div");
back.id="back";
var styleStr="top:0px;left:0px;position:absolute;background:#666;width:"+bWidth+"px;height:"+bHeight+"px;";
styleStr+=(isIe)?"filter:alpha(opacity=0);":"opacity:0;";
back.style.cssText=styleStr;
document.body.appendChild(back);
showBackground(back,50);
var mesW=document.createElement("div");
mesW.id="mesWindow";
mesW.className="mesWindow";
mesW.innerHTML="<div class='mesWindowTop'><table width='100%' height='100%'><tr><td>"+wTitle+"</td><td style='width:1px;'><input type='button' onclick='closeWindow();' title='關(guān)閉窗口' class='close' value='關(guān)閉' /></td></tr></table></div><div class='mesWindowContent' id='mesWindowContent'>"+content+"</div><div class='mesWindowBottom'></div>";
styleStr="left:"+(((pos.x-wWidth)>0)?(pos.x-wWidth):pos.x)+"px;top:"+(pos.y)+"px;position:absolute;width:"+wWidth+"px;";
mesW.style.cssText=styleStr;
document.body.appendChild(mesW);
}
//讓背景漸漸變暗
function showBackground(obj,endInt)
{
if(isIe)
{
obj.filters.alpha.opacity+=1;
if(obj.filters.alpha.opacity<endInt)
{
setTimeout(function(){showBackground(obj,endInt)},5);
}
}else{
var al=parseFloat(obj.style.opacity);al+=0.01;
obj.style.opacity=al;
if(al<(endInt/100))
{setTimeout(function(){showBackground(obj,endInt)},5);}
}
}
//關(guān)閉窗口
function closeWindow()
{
if(document.getElementById('back')!=null)
{
document.getElementById('back').parentNode.removeChild(document.getElementById('back'));
}
if(document.getElementById('mesWindow')!=null)
{
document.getElementById('mesWindow').parentNode.removeChild(document.getElementById('mesWindow'));
}
if(isIe){
setSelectState('');}
}
//測試彈出
function testMessageBox(ev)
{
var objPos = mousePosition(ev);
messContent="<div style='padding:20px 0 20px 0;text-align:center'>消息正文</div>";
showMessageBox('窗口標(biāo)題',messContent,objPos,350);
}
</script>
</head>
<body>
<div>
<div;><a href="#none" onclick="testMessageBox(event);">彈出窗口</a></div>
<div;><select ID="Select1" NAME="Select1"><option>下拉</option></select>彈出窗口時會將其隱藏，關(guān)閉時會讓其顯示，目的是在IE中防止彈出的DIV擋不住下拉框</div>
<div;><a href="#none" onclick="testMessageBox(event);">彈出窗口</a></div>
<div;><a href="#none" onclick="testMessageBox(event);">彈出窗口</a></div>
</div>
<br />
</body>
</html>
希望本文所述對大家JavaScript程序設(shè)計有所幫助。