JS把光标聚焦到输入框里的文字的最后面

    <script language=javascript>
function behindWord()
{  
  var e = event.srcElement;  
  var r = e.createTextRange();  
  r.moveStart("character",e.value.length);  
  r.collapse(true);  
  r.select();  
}  

</script>

<input   type= "text "   onfocus= "behindWord() "   value= "tttt "/>