jQuery adding blank option field in the select box

Question

I have the following jquery code that is working for two select fields.

$(document).ready(function () {
    $("#select1").change(function(){
      $('#trblock').fadeIn();
      if ($(this).data('options') == undefined) {
        $(this).data('options', $('#select2 option').clone());
      }
      var id = $(this).val();
      var options = $(this).data('options').filter('[value=' + id + ']');
      $('#select2').html(options);
    });
});

However I want the second select box having id="select2" to be loaded with 1 extra blank option at the top. I tried simply adding the HTML part but I think that due to the jQuery code effect above its not allowing it. So I think modifying the jQuery part instead will do the task. But I have a newbie to jQuery. Please help me how to get it.

Something like this in HTML.

<select name="" id="select2">
<option value=""></option> // I want this here (by changing/adding codes in jquery)
<option value="1" date="01">Value 1</option>
<option value="2" date="02">Value 2</option>
<option value="3" date="03">Value 3</option>
<option value="4" date="04">Value 4</option>
<option value="5" date="05">Value 5</option>
</select>

Answer 1

First create the empty option, then add the rest with .append()

$(document).ready(function () {
    $("#select1").change(function(){
      $('#trblock').fadeIn();
      if ($(this).data('options') == undefined) {
        $(this).data('options', $('#select2 option').clone());
      }
      var id = $(this).val();
      var options = $(this).data('options').filter('[value=' + id + ']');
      $('#select2').html('<option value="">').append(options);
    });
});    

Answer 2

只需使用 jquery 的 prepend() 在顶部添加一个选项。

$('#select2').prepend('<option value="">');

Answer 3

If you wanna add the blank option in the starting and select it by default, use below code:

$("#id").prepend("<option value=' ' selected='selected'></option>");

prepend will add the option to top and selected='selected' will make it selected. As value=' ' , so, it is blank value option.

If you wanna just add the blank option and don't wanna select it by default then use below code:

$("#id").append("<option value=' ' ></option>");

Answer 4

The best way to do this if you are using form::select then use this inline [''=>'--- Select Subject - --']+$subjects

 $('#subject').select2({ placeholder: "Select Subject...", });

 <div class="col-md-6" id ='subjectDiv'> <div class="mb-3"> <div class="form-group"> {!! Form::label('subject', '* Subject:') !!} {!! Form::select('subject', [''=>'--- Select Subject - --']+$subjects, null, ['required' => true, 'class' => 'form-control', 'id'=>'subject'])!!} @if ($errors->has('subject')) <span class="text-danger">{!! $errors-> first('subject') !!}</span> @endif <small id="" class="form-text text-muted"></small> </div> </div> </div>