This should work for what you're wanting to do.
<form name=form1>
<select name=jump onchange=window.open(document.form1.jump.options[document.form1.jump.selectedIndex].value)>
<option value="page1.html">page 1</option>
<option value="page2.html">page 2</option>
<option value="page3.html">page 3</option>
</select>
</form>
