Javascript-Auto call function

onLoad=window.setTimeout("StartText(25)",100);
var y
var timerID = 0;
function StartText(x)
{
document.getElementById ('AdOrCon').style .fontSize =x+"px";
if (x==40)
{y=1;}
else{
y=x+1;}
clearTimeout(timerID);
timerID=0;
timerID=setTimeout("StartText(y)",100);
}
function showTab(x)
{
document.getElementById('Div1').style.display="none";
document.getElementById('Div2').style.display="none";
document.getElementById('Div3').style.display="none";
document.getElementById('Div4').style.display="none";
document.getElementById('Div5').style.display="none";
document.getElementById('Div'+x).style.display="";
if (x==5)
{ y=1 ;}
else
{ y=x+1; }
clearTimeout(timerID);
timerID=0;
timerID = setTimeout("showTab(y)", 10000);

}