JavaScript下拉框去除重复内容

<script type="text/javascript" src="http://www.joleye.com/libraries/javascript/jquery-1.5.1.min.js"></script>
<a href="###">加载</a>
<select>
</select>

<a href="###">加载</a>
<select>
</select>

<a href="###">加载</a>
<select>
</select>

<a href="###">加载</a>
<select>
</select>

<a href="###">加载</a>
<select>
</select>

<a href="###">加载</a>
<select>
</select>

<script>
var option = [
    {
        value : ‘‘,
        text : ‘--请选择--‘
    },
    {
        value : ‘1‘,
        text : ‘java‘
    },
    {
        value : ‘2‘,
        text : ‘.net‘
    },
    {
        value : ‘3‘,
        text : ‘python‘
    }
];

$(‘a‘).click(function(){
    
    var t = $(this).next();
    
    if(t.val()!=null){
        t.empty();
    }
    
    var tar = {};
    
    $(‘select option:selected‘).each(function(){
        if($(this).val() != ‘‘)
            tar[$(this).val()] = 1;
    });
    
    
    var newoption = [];
    $.each(option,function(i,val){
        if(!tar[val.value]){
            newoption.push(val);
        }
    });
    
    $.each(newoption,function(i,val){
        $(‘<option value="‘+val.value+‘">‘+val.text+‘</option>‘).appendTo(t);
    });
    
});
</script>