Develop Reference

How to use getElementByID in JavaScript to connect to my HTML drop down box?

I have a drop-down box in HTML showing three options. I am also using javaScript and want to use the getElementById tool to connect the two. However, I only have one ID for the drop-down box. How does javascript recognize that I have three different options?

There's actually a demo on w3schools.com showing exactly what you're asking. To get the number of options, you could do something like
document.getElementById("mySelect").options.length

Here is an example of how to retrieve the value of a dropdown: https://jsfiddle.net/ykcwgnm8/
You use getElementBy* functions to get the element, however value attribute denotes which item is currently selected.
HTML:
<select id="dropdown">
<option value="1">First option</option>
<option value="2">Second option</option>
<option value="3">Third option</option>
</select>
JS:
function onChangeHandler(e)
{
alert("you have selected item with value "+this.value);
}
document.getElementById("dropdown").addEventListener("change", onChangeHandler);

You can listen for change like this
var list = document.getElementById("mySelect")
list.addEventListener('change', function(e){
console.log(e.target.selectedIndex)
console.log(e.target.options[e.target.selectedIndex].text)
})
<select id="mySelect">
<option>Apple</option>
<option>Orange</option>
<option>Pineapple</option>
<option>Banana</option>
</select>

You can do something like this, here is an example:-
html
<select id="selectBox">
<option value="1">option 1</option>
<option value="2" selected="selected">option 2</option>
<option value="3">option 3</option>
</select>
js
var e = document.getElementById("selectBox");
var selectedValue = e.options[e.selectedIndex].value;
// this will give selectedValue as 2
Hope you find this useful!!

Awesomplete - Take option value

I asked a question about of typeahead but nobody answered me and i change plugin and i used Awesomplete from this link:
Awesomplete plugin
Now I ask how can I take an option value from this code in jQuery inside awesomplete.js code:
<input id="testoNome" class="awesomplete testocss" style="width:166 !important;" autocomplete="off" aria-autocomplete="list">
<datalist id="listClienti">
<option value="1">Cristian Capannini</option>
<option value="2">Cristopher Capannini</option>
<option value="3">Luigi Russo</option>
<option value="4">Luca Russo</option>
<option value="25">dsfsdf dsfsdf</option>
<option value="26">asdasd asdasdasd</option>
<option value="27">11111 11111</option>
<option value="28">Luca Cecchini</option>
<option value="29">xxxxx xxxxx</option>
<option value="30">Maurizio Pippetta</option>
<option value="31">Maurizio Pippetta</option>
<option value="32">Pinco Pallino</option>
<option value="33">sfsf sdfsdf</option>
</datalist>

It was a bit tricky but i got it for my ajax-generated list. Try it for your static version:
$yourAwesomeplete.on('awesomplete-selectcomplete', function(e) {
value = e.originalEvent.text.value;
label = e.originalEvent.text.label;
});

Using jQuery, you can get the selected value by using this code
$(".awesomplete input").val()

Javascript - Get atribute from select menu

Hello there dear community.
Here is my HTML code:
<select name="Pcolor" id="image" style="height:30px;">
<option value="">Избран цвят: Blue/Lt Blue </option>
<option value="45751303" color-number="0">Black</option>
<option value="45751343" color-number="1">Black/Pink</option>
<option value="45751359" color-number="2">Blue/Lt Blue</option>
<option value="45751324" color-number="3">Dk Purple/Purpl</option>
<option value="45751390" color-number="4">Ink/Cerise</option>
</select>
I want to ask how i can get the color-number attribute number where option text is Blue/Lt Blue for example ?
It is important to make it only with JavaScript/jQuery !
I hope you understand what i want to describe, thanks in advance!

I would do this way:
$('#image option[value="Blue/Lt Blue"]').attr("color-number");
So essentially you search for the correct option and get it attribute.

Using :contains() won't be a proper solution as it will return partial matches, instead you can use .filter()
var text = 'Black/Pink';
var cn = $('select[name="Pcolor"] option').filter(function() {
return $(this).text().trim() == text;
}).attr('color-number');
console.log(cn)
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<select name="Pcolor" id="image" style="height:30px;">
<option value="">Избран цвят: Blue/Lt Blue</option>
<option value="45751303" color-number="0">Black</option>
<option value="45751343" color-number="1">Black/Pink</option>
<option value="45751359" color-number="2">Blue/Lt Blue</option>
<option value="45751324" color-number="3">Dk Purple/Purpl</option>
<option value="45751390" color-number="4">Ink/Cerise</option>
</select>

$('#image').on('change',function() {
alert($(this).find('option:selected').attr('color-number'));
})
https://jsfiddle.net/cw6knsc5/2/

select option using jquery fails?

Here iam trying to get values based on #category selection when i select a category men or women,following select option should show the relevant options.what i did satisfied my requirement but when i try to access it using keyboard(down arrow) it shows all the options of the #subcategory.here is the code and fiddle.any help is thankful.
my fiddle http://jsfiddle.net/JUGWU/
HTML:
<select id="category" name="category">
<option>-select-</option>
<option value="MEN" id="menu1">MEN</option>
<option value="WOMEN" id="menu2">WOMEN</option>
</select>
<br>
<select id="subcategory">
<option></option>
<option id="Clothing" value="Clothing">Clothing</option>
<option id="Accessories" value="Accessories">Accessories</option>
<option id="Footwear" value="Footwear">Footwear</option>
<option id="Watches" value="Watches">Watches</option>
<option id="Sunglasses" value="Sunglasses">Sunglasses</option>
<option id="Bags" value="Bags">Bags</option>
</select>
Jquery:
$(document).ready(function(){
$("#category").change(function() {
var xyz = $("option:selected").attr("id");
alert(xyz);
if(xyz === "menu1"){
$("#subcategory option").hide();
$("#Clothing,#Footwear").show();
}
});
});

Try this in your conditional. The disabled property doesn't allow keyboard selection. Seems to work for me.
$("#subcategory option").prop('disabled', true).hide();
$("#Clothing,#Footwear").prop('disabled', false).show();
Also, your logic breaks if a user switches from men to women.

This answer is not exactly addressing your problem (using keyboard(down arrow)) but I think it is IMHO a better way to do what you want. And also I used the fixed part from #user2301903 answer, just to make my point. my main point here was using the markup attributes.
We can use our markup attributes to have less complexity, I changed your markup like this (added a catg attribute):
<select id="category" name="category">
<option>-select-</option>
<option value="MEN" id="menu1" catg="m">MEN</option>
<option value="WOMEN" id="menu2" catg="w">WOMEN</option>
</select>
<br>
<select id="subcategory">
<option></option>
<option id="Clothing" value="Clothing" catg="m">Clothing</option>
<option id="Accessories" value="Accessories" catg="w">Accessories</option>
<option id="Footwear" value="Footwear" catg="m">Footwear</option>
<option id="Watches" value="Watches" catg="w">Watches</option>
<option id="Sunglasses" value="Sunglasses" catg="w">Sunglasses</option>
<option id="Bags" value="Bags" catg="w">Bags</option>
</select>
and your code like this:
$(document).ready(function () {
$("#category").change(function () {
var catg = $("option:selected").attr("catg");
//from #user2301903 answer
$("#subcategory option").prop('disabled', true).hide();
$("option[catg=" + catg + "]").prop('disabled', false).show();
});
});
and this is your working DEMO;
and this one is another way of doing what you want which works even in IE: IE_DEMO

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>

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.

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");
}
});

$('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;
});