textarea自动滚动效果

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<SCRIPT LANGUAGE="JavaScript">
<!--
function cc()
{
var e = event.srcElement;
var r =e.createTextRange();
r.moveStart('character',e.value.length);
r.collapse(true);
r.select();
}//-->
</SCRIPT>
</HEAD><BODY>
<TEXTAREA NAME="" ROWS="" COLS=""  onfocus="cc()" >
asdfa
sdf
sdf
sdf
sdf
sdfsdf
sdf
sdf
sdfsdf
sdf
sdfsdf
</TEXTAREA>
</BODY>
</HTML>