Loading image while waiting

Sometimes we want to show kind of a "waiting" image while a page is been rendered or while we are waiting for a server response.
It's easy, we just need: some css style, a .gif image, a javascript.
Following code is supporting cross-browsing:

The css classes:

.loadingDiv 
{ 
    z-index: 1000; 
    position:relative; 
    top:1200px; 
    float: left; 
    width:100%; 
    background-color:White; 
    opacity: 0.7; 
    padding-top:300px; 
    margin-top:-1200px; 
  } 
 
.loadingImage 
{ 
    margin-left: auto; 
    margin-right:auto; 
    padding-bottom:600px; 
} 

Here are the div and the img element. Place them in the top of the page inside the body tag:

<div id="loading" class="loadingDiv"> 
    <img id="imgMainLoadImage" src="../images/loading.gif" border="0" alt="" class="loadingImage" /> 
</div> 

Here is the script. Place it just below the div, no matter if you have any other block of scripts in other sections in the page.

<script> 
    var ld = (document.all); 
    var imgL = (document.all); 
    var ns4 = document.layers; 
    var ns6 = document.getElementById && !document.all; 
    var ie4 = document.all; 
    if (ns4) { 
  ld = document.loading; 
        imgL = document.imgMainLoadImage; 
    } 
    else if (ns6) { 
        ld = document.getElementById("loading").style; 
        imgL = document.getElementById("imgMainLoadImage").style; 
    } 
    else if (ie4) { 
        ld = document.all.loading.style; 
        imgL = document.all.imgMainLoadImage.style; 
    } 
 
    function init() { 
        if (ns4) { 
            ld.visibility = "hidden"; 
        } 
        else if (ns6 || ie4) { 
            ld.display = "none"; 
        } 
    } 
 
    function ShowLoadingImage() { 
        if (ns4) { 
            ld.visibility = "visible"; 
        } 
        else if (ns6 || ie4) { 
            ld.display = "block"; 
        } 
    } 
</script> 

The last and not least part is to call the javascript function in the "onload" event in the body.
I have used this in masterpages as well as content pages.

<body onload="init();">