实现网页在显示对话框时网页的内容不可操作

<div id="blockUI" class="translucent" style='display: none; background-color: gray;
        width: 100%; height: 100%; position: absolute; left: 0px; top: 0px; z-index: 50000;"
        onclick="return false" onmousedown="return false" onmousemove="return false"
        onmouseup="return false" ondblclick="return false">
        &nbsp;</div>

.translucent
{
filter:alpha(opacity=50);
-moz-opacity:0.5;
opacity:0.5;
}