如何使页面中的INPUT按指定的顺序移动焦点

<form   name= "frm "   action= "check.asp "   method= "post "> 
Third <input   type=text   name= "t1 "   tabindex= "3 "   value= "Third "   onfocus= "this.select(); "> 
Second <input   type=text   name= "t2 "   tabindex= "2 "   value= "Second "   onfocus= "this.select(); "> 
First <input   type=text   name= "t3 "   tabindex= "1 "   value= "First "   onfocus= "this.select(); "> 
<input   type=submit   name= "sub1 "   value= "Submit "> 
</form>