Searchable dropdown select

Componente para facilitar a carga de combos com ajax

HTML

<input type="text" id="input"/><br>
<select>
    
</select>
<select id="combo"></select>
<div id ="dropdown">
    <table>
        
    </table>
</div>

CSS

#dropdown > table > tbody > tr > td > a{
    width : 100%;    
    display : block;   
}
table{
    border-radius : 5px;
    border: solid 1px;    
}
input{
    border-radius : 5px;
}

JavaScript

$.widget("custom.combo", {
    options : {
        loading : '<img alt="" id="loading"...