Get Selected Option by Value

Question

Firstly, apologize you find this really duplicates with other questions but since I'm already try most of the solutions given, but still stuck in the middle, then this is my last choice for getting the solutions. I've try the examples like this:

var user_dept = val[0].user_dept;
$('#user_dept option:selected').attr('value', user_dept);

and

var user_dept = val[0].user_dept;
$('#user_dept option[value="'+user_dept+'"]').attr('selected', true);

and as well this:

$('#user_dept').append($('<option>',{
        value: val[0].user_dept,
      }));

But couldn't get the issues solved. FYI, I declare all these codes inside if statement on jQuery. Wish to get the answers for jquery if possible since I'm using jquery for my work.

Edited:

As I mention on these comments below, I get the select option generated by this function,

function UserDept()
{
  $.getJSON('user_management_lib.php?mode=getDepartmentList', function(data){
    var list = [];
    $.each(data, function(index, value){
      list += '<option value="'+value['department_id']+'">'+value['department']+'</option>'
    });
    $('#user_dept').html(list);
  });
}

But as for selected option, I need to get this done by value which are equal to user_dept column from distinct table which is totally unrelated to function above. Since I use jQuery and array, I will declare this in $('#user_dept').val(val[0].user_dept);. I will clarify if necessary. Sorry for any inconveniences.

Edited on 30/12/2016: Code below is the callback function using ajax where this question also included. So, it's quite incomplete since I'm playing around to fix this.

$.ajax({
  cache: false,
  url: 'ldap_lib.php',
  data:'mode=findLDAPServerInfo&ldapid=<?php echo $target_lid; ?>',
  type:'POST',
  dataType:'json',
  success: function(val){
    UserDept();
    UserRole();
    GlobalDept();
    $('#mode').val('editLDAPServer');
    $('#l_name').val(val[0].l_name);
    $('#l_desc').val(val[0].l_desc);
    $('#l_ip1').val(val[0].l_ip1);
    $('#l_port1').val(val[0].l_port1);
    $('#l_ip2').val(val[0].l_ip2);
    $('#l_port2').val(val[0].l_port2);
    $('#l_domainname').val(val[0].l_domain);
    $('#l_loginname').val(val[0].l_loginname);
    $('#l_loginpwd').val(val[0].l_loginpwd);
    $('#l_mobile').val(val[0].l_mobile);
    $('#l_basedn').val(val[0].l_basedn);
    $('#l_filter').val(val[0].l_filter);
    $('#l_type').val(val[0].l_type);
    $('#l_loginmode').val(val[0].l_loginmode);
    $('#l_scope').val(val[0].l_scope);
    $('#sync_frequency').val(val[0].sync_frequency);
    $('#sync_time').val(val[0].sync_hour);

    if(val[0].sync_ul == 't'){
      $('#l_sync_ul').prop('checked', true);
      $('#tip_ul_dept').attr('style','display:block');
      var user_dept = val[0].user_dept;
      var user_role = val[0].user_role;
      //$('#user_dept option[value="'+user_dept+'"]').attr('selected', true);
      //$('#user_role option[value="'+user_role+'"]').attr('selected', true);
      //$('#user_dept option:selected').attr('value', user_dept);
      console.log($("#user_dept option"));
    } else{
      $('#l_sync_ul').prop('checked', false);
      $('#tip_ul_dept').attr('style','display:none');
    }
    if(val[0].sync_gab == 't'){
      $('#l_sync_gab').prop('checked', true);
      $('#tip_gab_dept').attr('style','display:block');
      // $('#gab_dept').val(val[0].gab_dept);
    } else{
      $('#l_sync_gab').prop('checked', false);
      $('#tip_gab_dept').attr('style','display:none');
    }
    //$('#gab_dept').val(val[0].gab_dept);
    $('#user_dept').val(val[0].user_dept);
  },
  error: function(){
    alert('Failed To Retrieve Server');
  }
});

Answer 1

If you are simply trying to get the value of the select element, that is, the value of the currently selected option element belonging to the select element, you can use jQuery's .val() function: $('#user_dept').val().

If you are trying to get the option element which has a given value, as your post title indicates, use $('#user_dept option(value="' + val + '")').

The above assumes that val is a string/string-like value - you've used val[0] in your code sample which indicates val is an array. Use val[0] if that's the case.

Edit You are trying to set the value of the select element before the select options have been created (they're generated asynchronously from a JSON request).

Make sure that the options have been generated before doing this - I've updated your JSFiddle with an example of how you might do this.