<form name="form1">
<select name="menu1" id="menu1">
<option value="http://www.espn.com">ESPN</option>
<option value="http://www.cnn.com">CNN</option>
<option value="http://www.abcnews.com">ABC</option>
<option value="http://www.cbsnews.com">CBS</option>
<option value="http://www.foxnews.com">FOX</option>
</select>
<script type="text/javascript">
 var urlmenu = document.getElementById( 'menu1' );
 urlmenu.onchange = function() {
      window.open(  this.options[ this.selectedIndex ].value );
 };
</script>