JQuery - how to select dropdown item based on value

I want set a dropdown(select) to be change based on the value of the entries.

I have

<select id="mySelect">
  <option value="ps">Please Select</option>
  <option value="ab">Fred</option>
  <option value="fg">George</option>
  <option value="ac">Dave</option>
</select>

And I know that I want to change the dropdown so that the option with the value of "fg" is selected. How can I do this with JQuery?

You should use

$('#dropdownid').val('selectedvalue');

Here's an example:

$('#dropdownid').val('selectedvalue');

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select id='dropdownid'>
    <option value=''>- Please choose -</option>
    <option value='1'>1</option>
    <option value='2'>2</option>
    <option value='selectedvalue'>There we go!</option>
    <option value='3'>3</option>
    <option value='4'>4</option>
    <option value='5'>5</option>
</select>

$('#yourdropddownid').val('fg');

Optionally,

$('select>option:eq(3)').attr('selected', true);

where 3 is the index of the option you want.

Live Demo

$('#mySelect').val('fg');...........

 $('#mySelect').val('ab').change();

 // or

 $('#mySelect').val('ab').trigger("change");

You can use this jQuery code which I find it eaiser to use:

$('#your_id [value=3]').attr('selected', 'true');

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<select id="your_id" name="name" class="form-control input-md">
  <option value="1">Option #1</option>
  <option value="2">Option #2</option>
  <option value="3">Option #3</option>
  <option value="4">Option #4</option>
  <option value="5">Option #5</option>
  <option value="6">Option #6</option>
  <option value="7">Option #7</option>
</select>

You can simply use:

$('#select_id').val('fg')

In your case $("#mySelect").val("fg") :)

May be too late to answer, but at least some one will get help.

You can try two options:

This is the result when you want to assign based on index value, where '0' is Index.

 $('#mySelect').prop('selectedIndex', 0);

don't use 'attr' since it is deprecated with latest jquery.

When you want to select based on option value then choose this :

 $('#mySelect').val('fg');

where 'fg' is the option value

$('#dropdownid').val('selectedvalue');

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select id='dropdownid'>
    <option value=''>- Please choose -</option>
    <option value='1'>1</option>
    <option value='2'>2</option>
    <option value='selectedvalue'>There we go!</option>
    <option value='3'>3</option>
    <option value='4'>4</option>
    <option value='5'>5</option>
</select>

This code worked for me:

$(function() {
    $('[id=mycolors] option').filter(function() { 
        return ($(this).text() == 'Green'); //To select Green
    }).prop('selected', true);
});

With this HTML select list:

<select id="mycolors">
      <option value="1">Red</option>
      <option value="2">Green</option>
      <option value="3">Blue</option>
</select>

You can select dropdown option value by name

// deom
jQuery("#option_id").find("option:contains('Monday')").each(function()
{
 if( jQuery(this).text() == 'Monday' )
 {
  jQuery(this).attr("selected","selected");
  }

});

I have a different situation, where the drop down list values are already hard coded. There are only 12 districts so the jQuery Autocomplete UI control isn't populated by code.

The solution is much easier. Because I had to wade through other posts where it was assumed the control was being dynamically loaded, wasn't finding what I needed and then finally figured it out.

So where you have HTML as below, setting the selected index is set like this, note the -input part, which is in addition to the drop down id:

$('#project-locationSearch-dist-input').val('1');

                <label id="lblDistDDL" for="project-locationSearch-input-dist" title="Select a district to populate SPNs and PIDs or enter a known SPN or PID." class="control-label">District</label>
                <select id="project-locationSearch-dist" data-tabindex="1">
                    <option id="optDistrictOne" value="01">1</option>
                    <option id="optDistrictTwo" value="02">2</option>
                    <option id="optDistrictThree" value="03">3</option>
                    <option id="optDistrictFour" value="04">4</option>
                    <option id="optDistrictFive" value="05">5</option>
                    <option id="optDistrictSix" value="06">6</option>
                    <option id="optDistrictSeven" value="07">7</option>
                    <option id="optDistrictEight" value="08">8</option>
                    <option id="optDistrictNine" value="09">9</option>
                    <option id="optDistrictTen" value="10">10</option>
                    <option id="optDistrictEleven" value="11">11</option>
                    <option id="optDistrictTwelve" value="12">12</option>
                </select>

Something else figured out about the Autocomplete control is how to properly disable/empty it. We have 3 controls working together, 2 of them mutually exclusive:

//SPN
spnDDL.combobox({
    select: function (event, ui) {
        var spnVal = spnDDL.val();
        //fire search event
        $('#project-locationSearch-pid-input').val('');
        $('#project-locationSearch-pid-input').prop('disabled', true);
        pidDDL.empty(); //empty the pid list
    }
});
//get the labels so we have their tool tips to hand.
//this way we don't set id values on each label
spnDDL.siblings('label').tooltip();

//PID
pidDDL.combobox({
    select: function (event, ui) {
        var pidVal = pidDDL.val();
        //fire search event
        $('#project-locationSearch-spn-input').val('');
        $('#project-locationSearch-spn-input').prop('disabled', true);
        spnDDL.empty(); //empty the spn list
    }
});

Some of this is beyond the scope of the post and I don't know where to put it exactly. Since this is very helpful and took some time to figure out, it's being shared.

Und Also ... to enable a control like this, it's (disabled, false) and NOT (enabled, true) -- that also took a bit of time to figure out. :)

The only other thing to note, much in addition to the post, is:

    /*
Note, when working with the jQuery Autocomplete UI control,
the xxx-input control is a text input created at the time a selection
from the drop down is picked.  Thus, it's created at that point in time
and its value must be picked fresh.  Can't be put into a var and re-used
like the drop down list part of the UI control.  So you get spnDDL.empty()
where spnDDL is a var created like var spnDDL = $('#spnDDL);  But you can't
do this with the input part of the control.  Winded explanation, yes.  That's how
I have to do my notes or 6 months from now I won't know what a short hand note means
at all. :) 
*/
    //district
    $('#project-locationSearch-dist').combobox({
        select: function (event, ui) {
            //enable spn and pid drop downs
            $('#project-locationSearch-pid-input').prop('disabled', false);
            $('#project-locationSearch-spn-input').prop('disabled', false);
            //clear them of old values
            pidDDL.empty();
            spnDDL.empty();
            //get new values
            GetSPNsByDistrict(districtDDL.val());
            GetPIDsByDistrict(districtDDL.val());
        }
    });

All shared because it took too long to learn these things on the fly. Hope this is helpful.

$('select#myselect option[value="ab"]')

either can be used to get the selected option value

$('#dropdownID').on('change', function () {
        var dropdownselected=$("#dropdownID option:selected").val();
		});
	 
	 or 
	 
	 $('#dropdownID').on('change', function () {
        var dropdownselected=this.selectedOptions[0].value;
     });