css div实现的遮罩层完美兼容IE6-IE9 FireFox

<div id="black_overlay" style="display: none;"></div>
<div style="display: none;" id="load_content" >
<div style="float: left; padding-: 12px; padding-left: 5px;">
<img src="images/progressBar.gif" />
</div>
<div style="float: left; padding-: 15px;">数据加载中，请稍后...</div>
</div>

/loading加载遮罩层css/
#black_overlay
{
position: fixed;
z-index: 1000;
width: 100%;
height: 100%;
: 0;
left: 0;
filter: alpha(opacity=80);
opacity: 0.8;
overflow: hidden;
background-color: #000;
}
html
{
background: url() fixed;
}
html body
{
margin: 0;
height: 100%;
}
/IE6/
html #black_overlay
{
position: absolute;
left: expression(documentElement.scrollLeft + documentElement.clientWidth - this.offsetWidth);
: expression(documentElement.scrollTop + documentElement.clientHeight - this.offsetHeight);
}
#load_content
{
display: none;
position: absolute;
: 40%;
left: 40%;
width: 200px;
height: 50px;
border: 16px solid #FFF;
border-bottom: none;
background-color: white;
z-index: 1002;
overflow: auto;
font-size: 14px;
font-weight: bold;
}