將游標定位到textarea的某一行的javascript代碼

<textarea name="ta1" rows=5 cols=50>
aaaaaaaaaaaaaa

cccccccccc
dddddddddddd
fffffffffffff
</textarea>
<input value="1" name="line">
<input type=button onclick="goL(parseInt(line.value));" value="go">
<script>
function goL(Line)
{
ta1.focus();
var v=ta1.value.split('\n');
ch=0;
for(var i=0;i<Line-1;i++)
ch+=v[i].length;
var o=ta1.createTextRange();
o.move("character",ch);
o.select();
}
</script><textarea name="ta1" rows="5" cols="50"><br /> aaaaaaaaaaaaaa<br /> bbbbbbbbbbbbbb<br /> cccccccccc<br /> dddddddddddd<br /> fffffffffffff </p><p> <input value="1" name="line"><input type="button" onclick="goL(parseInt(line.value));" value="go">
[Ctrl+A 全選 注:如需引入外部Js需重新整理才能執行]