[devote]

<script type="text/javascript">
function selChange( self ) {
    var links = ['',
      '/xxxx.html',
      'zzzz.html'
    ];
    if ( links[ self.value ] ) {
        showContent( links[ self.value ] );
    }
}
</script>
<select onchange="selChange( this )">
    <option value="0"> - выберите вариант - </option>
    <option value="1">вариант 1</option>
    <option value="2">вариант 2</option>
</select>