Ekranın solunda buyuyerek acılan buton

<script languge=javascript>
var x=0; var y=0; 
function gs()
{
caner.style.width=x;
caner.style.height=y;
x=x+1;
y=y+1;



setTimeout("gs()", 50);
if (x==300 && y==300) {
y=50;
x=50;
}
}
</script>
<button onclick=gs() id=caner style="width:50px; height=50px;">tıkla</button>