ajax web页面复杂处理延时、客户交互问题

<script type="text/javascript">
function Wait()
{
    var child=document.createElement("div");
    child.id="looder";
    child.style.top =300;   
    child.style.left  = 300;   
    child.style.position="absolute";
    child.innerHTML="<img src='../img/loadingAnimation.gif'/>";  
     
    document.body.appendChild(child);
    child.focus();
    
}
</script>

this.Button1.Attributes.Add("onclick", this.Page.ClientScript.GetPostBackEventReference(Button1, "Click") + ";this.disabled=true; this.value='初始化..';Wait();");