i have two select box, now what i want is i want to move option from one select box to another via a button

below is my code:

php

<table>
    <tr>
        <td>
        <select  size="5" id="suppliedMovies" name="suppliedMovies">
            <option selected="selected" value="">Select Movie</option>          
            <option value="1">sholay</option>
            <option value="3">Jism</option>
            <option value="4">Rog</option>
            <option value="5">Zeher</option>
            <option value="6">Awarpan</option>
            <option value="7">Paap</option>
            <option value="8">paanch<option>
            <option value="9">no entry</option>
        </select>
        </td>
        <td>
            <input type="button" id="toRight" value="&gt;&gt;"><br>
            <input type="button" id="toLeft" value="&lt;&lt;">
       </td>
       <td>
        <select size="5" id="accquiredMovies" name="accquiredMovies">   
            <option> No item right now</option>
        </select>
       </td>
   </tr>
</table>

Jquery

jQuery(document).ready( function() {

 function displayVals() {
      var myValues = jQuery("#suppliedMovies").val();
      return myValues;
    }

    jQuery('#toRight').click(function(){
    var x=displayVals(); 
    console.log(x);
    var txt=jQuery("#suppliedMovies option[value='"+x+"']").text();
    console.log(txt);
    if(x!=''){
    jQuery('#accquiredMovies').append("<option value='"+x+"' >"+txt+"</option>");
    }           
    });         
});

i m using above jQuery, that is working fine but, i want that

when one item is copy from one select box to another select box, then that item should be disable(or probably delete) from first select box (to prevent duplicate entry). i also want to move item from right to left select box please suggest me optimized jQuery . Thanks.

UPDATE

if i want to use multiple select box on both side? then how do i use that?

more update

if i click on a item on rightselectbox and move it to left selectbox, and go further(post) then on right selectbox, there is nothing selected items?? what i need is on right selectbox, there all items shoud be always selected , otherwise what i need to do? after i move an item from right to left ,i again have to select rest of items on right selectbox and go further