[bushstas]

<select id="list" multiple="multiple" size=7>
 <option value="option1" selected>Option 1</option>
 <option value="option2">Option 2</option>
 <option value="option3">Option 3</option>
 <option value="option3">Option 4</option>
 <option value="option3">Option 5</option>
 <option value="option3">Option 6</option>
 <option value="option3">Option 7</option> 
 <option value="option3">Option 8</option>
 <option value="option3">Option 9</option> 
 </select>


 <button id="mup" onclick="Select_up()">Move Up</button>
 <button id="mdown" onclick="Select_down()">Move Down</button>
 <script>

function Select_down(){var e=document.getElementById('list'),q=e.options.length,cur=e.selectedIndex
e.selectedIndex=cur<q-1?cur+1:cur
}

function Select_up(){var e=document.getElementById('list'),cur=e.selectedIndex
e.selectedIndex=cur>0?cur-1:cur
}

</script>