The 'loader' function allows you to define how to load data from remote server, please try the code below:
$('#cc').combobox({
loader: function(param,success,error){
var opts = $(this).combobox('options');
if (!opts.url) return false;
$.ajax({
type: opts.method,
url: opts.url,
data: param,
async: false,
dataType: 'json',
success: function(data){
success(data);
},
error: function(){
error.apply(this, arguments);
}
});
}
})