Drop menu in new window

How could I get the following links to open in a new window (e.g._blank)?

<form name=“menuform”>
<select name=“menu1”>
<option value=“http://www.google.com” selected>Google</option>
<option value=“http://www.kirupa.com”>Kirupa</option>
</select>
<input type=“button” name=“Submit” value=“Go”
onClick=“top.location.href = this.form.menu1.options[this.form.menu1.selectedIndex].value;
return false;”>
</form>