<script language="vbscript">
<!--
Sub TextBox1_onkeydown                             //TextBox1,TextBox2,DropDownList1为web控件;
 if window.event.keyCode=13 then
  EnterTextBox_1.TextBox2.focus()     //EnterTextBox_1为 <form id=" EnterTextBox_1" runat="server">
 end if
End Sub
Sub TextBox2_onkeydown
 if window.event.keyCode=13 then
  EnterTextBox_1.DropDownList1.focus()
 end if
End Sub
Sub DropDownList1_onkeydown
 if window.event.keyCode=13 then
  EnterTextBox_1.TextBox1.focus()
 end if
End Sub
//-->
  </script>

另外一种:

<script language="vbscript">
<!--
Sub document_onkeydown
 if window.event.keyCode=13 then
  window.event.keyCode=9
 end if
End Sub
//-->
  </script>