Set Transparency for DIV Control.

This is for IE

objDiv.Style.Add("filter", "alpha(opacity=10)")
objDiv.Style.Add("-moz-opacity", "0.1")
objDiv.Style.Add("opacity", "0.1")

IE Encounetered problem creates when you close your browser.

This error comes due to -
if you are using window.location.reload(); in page onunload method.