How to make the input selected when the page is opened? _Form effects

<table cellspacing="0" cellpadding="0" width="600" border="0"> <tbody> <tr valign="top"> <td height="62"> <form name="f" action="http://www.baidu.com/s"> <input class="kw" maxlength="100" size="36" name="wd"><input type="hidden" value="3" name="cl"> <input class="sb" type="submit" value="百度搜索"> </form> </td> </tr> </tbody> </table>
[Ctrl A select all Note: If you need to introduce external Js, you need to refresh to execute ]