JQuery Select2 - How to select all options

Question

I'm using jQuery select2 multi select dropdown. I need to select all options in a dropdown from code. Basically there is a Select All checkbox on which this functionality has to be implemented, I want to select/deselect options from this checkbox.

Answer 1

using Select 2 DEMO

$("#e1").select2();
$("#checkbox").click(function(){
    if($("#checkbox").is(':checked') ){
        $("#e1 > option").prop("selected","selected");// Select All Options
        $("#e1").trigger("change");// Trigger change to select 2
    }else{
        $("#e1 > option").removeAttr("selected");
        $("#e1").trigger("change");// Trigger change to select 2
     }
});

$("#button").click(function(){
       alert($("#e1").val());
});
<select multiple id="e1" style="width:300px">
        <option value="AL">Alabama</option>
        <option value="Am">Amalapuram</option>
        <option value="An">Anakapalli</option>
        <option value="Ak">Akkayapalem</option>
        <option value="WY">Wyoming</option>
    </select>
<input type="checkbox" id="checkbox" >Select All

<input type="button" id="button" value="check Selected">

You need code As shown in DEMO2 for Simple Select

$("#checkbox").click(function(){
    if($("#checkbox").is(':checked') ){
        $("select > option").prop("selected","selected");
    }else{
        $("select > option").removeAttr("selected");
     }
});

$("#button").click(function(){
       alert($("select").val());
});

<select multiple size=2>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="opel">Opel</option>
  <option value="audi">Audi</option>
</select> <input type="checkbox" id="checkbox" >Select All

<input type="button" id="button" value="check Selected">