var bShowTopOfpageButton = false;

function doClick()
{
	if (event.srcElement.id == "TopOfPageButton")
	{
		// process click
		window.scrollTo (0,0);
		document.body.all.TopOfPageButton.style.visibility = "hidden";
		if ( bShowTopOfpageButton == true )
		{
			window.clearTimeout ( timerID );
			bShowTopOfpageButton = false;			
		}
	}
}


function window_onscroll()
{
	if ( bShowTopOfpageButton == true )
		window.clearTimeout ( timerID );

	timerID = window.setTimeout ( "HandleScrollTimeout()",500 );
	bShowTopOfpageButton = true;
}

function HandleScrollTimeout()
{
	if ( bShowTopOfpageButton == true )
	{
		document.body.all.TopOfPageButton.style.visibility = "visible";
		document.body.all.TopOfPageButton.style.top = document.body.scrollTop + document.body.offsetHeight/2 -  document.body.all.TopOfPageButton.offsetHeight/2;
		document.body.all.TopOfPageButton.style.left = document.body.offsetWidth - document.body.all.TopOfPageButton.offsetWidth - 30;
		bShowTopOfpageButton = false;
	}
}


window.onscroll = window_onscroll;
document.onclick = doClick;