var txtPromo = "This is the  Promo text.";
var loopCnt = 0;
var intShowing = 0;

function tick() 
{
	var objShowing = document.getElementById("tickdisp");
	if(loopCnt == 40) { objShowing.innerHTML = ""; loopCnt = 0; intShowing=0; }
	txtShowing = objShowing.innerHTML;
	intPromo = txtPromo.length;
	
	if(intShowing != intPromo)
	{
		intShowing++;
		objShowing.innerHTML = txtPromo.substring(0,intShowing) + "_"; 	
	}
	else
	{
		loopCnt++;
	}
	
	setTimeout("tick()",100);
}