Select2 doesn't show selected value - jquery-select2

Question

Select2 loads all items from my list successful, the issue I found when try to select a specific value when page loads. Example:
:: put select2 in a specific html element, no value is selected even all items are loaded.
$('#my_id').select2();
:: When the page is loaded I'm trying to show a specific item selected, but doesn't work as expected, because even selected, the select2 doesn't show it.
$('#my_id').val('3'); //select the right option, but doesn't render it on page loads.
How to make a selected option to pop up when pages loads?
Thanks in advance.
#UPDATED
:: How I load all select2 items (sorry, its jade, not pure HTML):
label(for='category') Category
span.required *
select(id='category', style='width:230px', name='category')
option(value='') - Select -
each cat in categories
option(value='#{cat.id}') #{cat.description}
P.S.: All items from my list are loaded.
:: How I initialize the select2:
Just put the following line code on my javascript and it does successful:
$('#category').select2();
:: How I'm trying to select a specific value:
First attempt:
$('#category').select2(
{
initSelection: function(element, callback) {
callback($('#field-category').val());
}
}
);
Second attempt:
$('#category').val($('#field-category').val());
P.S.: #field-category has a value its a hidden input field and works OK.

Answer 1

You need to use the initSelection option to set the initial value.
If you are using a pre-defined select element to create the select2, you can use the following method
$('select').select2().select2('val','3')
Demo: Fiddle

Answer 2

add a trigger change after setting val:
$('#my_id').val('3').trigger('change');

Answer 3

A very simple way to tackle this problem is :
//Step1: Here assuming id of your selectbox is my_id, so this will add selected attribute to 1st option
$('#my_id option').eq(0).prop('selected',true);
//Step2: Now reinitialize your select box
//This will work, if you haven't initialized selectbox
$('#my_id').select2();
or
//This will work, if you have initialized selectbox earlier, so destroy it first and initialise it
$('#my_id').select2('destroy').select2();

Answer 4

This may help:
$('#mySelect2').val('1'); // Select the option with a value of '1'
$('#mySelect2').trigger('change'); // Notify any JS components that the value changed
You can find more on details here:
Thanks

Answer 5

Per here initSelection is deprecated in Select2 4.0 and later.
Using Select2 4.0.0 this worked for me:
$('#my_id').select2({val:3});
HT: #Kokizzu

Answer 6

Here is how to make val in select2 just select the corresponding element.
For some reason, select2 doesn't provide the function to look up selections by id.
init:
$("#thing").select2({data:sources, initSelection: function(item, callback) {
// despite select2 having already read the whole sources list when you
// do .val(n) you have to explicitly tell it how to find that item again.
var to_be_selected = null;
$.each(sources, function(index, thing) {
if (thing.id == item.val()) {
to_be_selected = thing;
return;
}
})
callback(to_be_selected);
}})
normal code
// to load the thing with id==3 from the initial sources list.
$("#thing").select2({'val': 3})

Answer 7

For me I was sending selected in the data set still default option was not getting selected. I had to do something like below to make it work -
$(".select").select2({
data: data_names
});
data_names.forEach(function(name) {
if (name.selected) {
$(".select").select2('val', name.id);
}
});

Answer 8

I had a multiple select2 box with multiple selections.
Step 1 was to put my string of school_ids into an array of integers corresponding to the id of each school, and remove a leading zero. I had to do this in a separate script tag.
<script>
var school_ids = <%= raw JSON.parse(#search.school_ids).map{|x| x.to_i} - [0]%>
</script>
Step two was to create the select box, then set the values, then trigger like so:
<script>
$(document).ready(function() {
$('.select2-multiple').select2({
placeholder: "Hit Enter After Selection",
width: 'resolve'
});
$('.select2-multiple').val(school_ids);
$('.select2-multiple').trigger('change');
</script>

Answer 9

trigger just select2 to set the value
$('#my_id').val('3').trigger("change.select2");
and this will trigger select2 with dropdown
$('#my_id').val('3').trigger("change");

Answer 10

I meet with the same problem, this works for me：
Using Select2 > 4.0.0
$('#select_id').val('3').trigger('change');

Answer 11

var option=$(this);
if(option.val()==data.StudentCourses.CourseId)
{
option.setAttribute('Selected');
}
});
i have initilized select2 because i just want few options selected from them.

Answer 12

If you are using select2 v4.0.0 or above, you can check select2 documentation
// Initialize select2 for all select tags
$('select').select2();
// Initialize select2 for a specific id
$('#my-id').select2();
// Initialize select2 for a class
$('.my-class').select2();
// Update the displayed value after changing the selected option.
$('#my-id').trigger('change');

Answer 13

$('.classname').each(function() {
$(this).siblings().find('.select2selection__rendered').text($(this).text())
})
in my case I were dealing with a class then I used this way to set showing content at select2
<option selected value="your_value">your_text</option>
u need to put this at each select box's first option