问JQuery选择插件-将用户键入的输入发送到Ajax调用

EN

//initialization of chosen select
$(".chosen-select").chosen({
  search_contains: true // an option to search between words
});
$(".chosen-select-deselect").chosen({
  allow_single_deselect: true
});

//ajax function to search a new value to the dropdown list
function _ajaxSearch (param){
  return $.ajax({
    url: "request.php",
    type: "POST",
    dataType: "json",
    data: {param:param}
  })
}
//key event to call our ajax call
$(".chosen-choices input").on('keyup',function(){
  var  param = $('.chosen-choices input').val();// get the pressed key
  _ajaxSearch(param)
  .done(function(response){
    var exists; // variable that returns a true if the value already exists in our dropdown list
    $.each(response,function(index, el) { //loop to check if the value exists inside the list
      $('#mySelect option').each(function(){
        if (this.value == el.key) {
          exists = true;
        }
      });
      if (!exists) {// if the value does not exists, added it to the list
        $("#mySelect").append("<option value="+el.key+">"+el.value+"</option>");
        var ChosenInputValue = $('.chosen-choices input').val();//get the current value of the search
        $("#mySelect").trigger("chosen:updated");//update the list
        $('.chosen-choices input').val(ChosenInputValue);//since the update method reset the input fill the input with the value already typed
      }
    });
  })
})

if (isset($_POST["param"])) {// check is the param is set
$param = $_POST["param"]; // get the value of the param
$array  = array('JKL' => 'jkl' , 'MNO'=>'mno', 'PQR'=>'pqr','STU'=>'stu','VWX'=>'vwx','YZ'=>'yz' );//array of values
$matches = array();//array of matches
    foreach($array as $key=>$value){//loop to check the values
        //check for match.
        if(strpos($value, $param) !== false){
            //add to matches array.
            $matches[]= array ("key"=> $key,"value"=>$value);
        }
    }
//send the response using json format
echo json_encode($matches);
}