如何设置焦点在文本框的位置

Question

<input type=text id="box" value="123456789" NAME="box">
<input type=button onclick='Move(3)' value='check' name='test3' ID="Button1">
<script language=javascript>
function Move(n) 
{ 
var rng = box.createTextRange(); rng.moveStart("character",n) 
rng.collapse(true); rng.select(); } 
</script>

Answer 1

<input onfocus="sel(this,3)" name=txt value="123456">
<input type=button value=setFocus onclick="document.all.txt.focus()">
<script language=javascript>
function sel(obj,num)
{
   var rng=obj.createTextRange();
   rng.moveStart("character", num);
   rng.collapse(true);
   rng.select();
}
</script>

Answer 2

<input name="text1" value="123456">
<input name="button1" type="button" value="按" onclick=show()>
<script language=javascript>
function  show()
{
var obj=document.getElementById("text1")
var range=obj.createTextRange()
range.moveStart("character",3)
range.moveEnd("character",-3)
range.select()
}
</script>

Answer 3

<script type="text/javascript">
//<![CDATA[
 function t(oObj){
  var rg=oObj.createTextRange();
  var rg_=oObj.createTextRange();
rg.moveStart('character',2);
rg.collapse(true);
rg_.moveStart('character',4);
rg.setEndPoint('startToStart', rg_);
rg.select();
rg=rg_=null;
 }
//]]>
</script>
<input value="123456" id="nIpt" />
<button onclick="t(document.getElementById('nIpt'))">focusThat</button>