Impostare pulsante come predefinito

[badaze]

<input type="button" id="b1" value="Button 1">

<input type="button" id="b2" value="Button 2">

<input type="button" id="b3" value="Button 3">

<script language="JavaScript" type="text/javascript">
<!--
b2.setActive();
//-->
</script>