JQuery Multi Select Option - check if an option is selected or not.

Question

I have an HTML Multi select box

<form action="form_action.php" method="Post"> <select name="cars[]" multiple id="select_id"> <option value="all" id="option_id">All</option> <option value="volvo">Volvo</option> <option value="saab">Saab</option> <option value="opel">Opel</option> <option value="audi">Audi</option> </select> <input type="submit"> </form> 

What I'm trying to do is check if the "All" option is selected or not in jQuery.

What I tried

 <script> $(document).ready(function() { $('#option_id') .click( function() { if ($("#select_id option[value='all']").length == 0) { //value does not exist so add //Do something if not selected } else { //DO something if selected } //$("#select_id option:selected").removeAttr("selected"); //Remove //$("#select_id option").attr('selected', 'selected'); //Add } ); }); </script> 

But it does not work.

Can anybody help me?

Thanks in advance for your help.

Answer 1

Please do as below code

 $('#option_id').click(function(){ if ($("#select_id option[value=all]:selected").length > 0){ alert('all is selected'); } else{ //DO something if not selected } //$("#select_id option:selected").removeAttr("selected"); //Remove //$("#select_id option").attr('selected', 'selected'); //Add }); 

You can check below script

Multi select

Answer 2

You can use the :selected selector to choose whether it will be selected or not

 if ($("#select_id option[value=all]:selected").length > 0){ //all is selected } 

Answer 3

From what I see, you are trying to determine if it was selected when changing the parameter in the <select> field, right?

Try the following:

 $("#select_id").change(function () { if ($(this).find("option:selected").val() == "all") { // all is selected } else { // all isn't selected } });