Develop Reference

Javascript get specific values from array list

<select name="List" id="List">
<option value="">-Select-</option>
<option value="">--Product--</option>
<option value="">product1</option>
<option value="">product2</option>
<option value="">product3</option>
<option value="">--Software--</option>
<option value="">software1</option>
<option value="">software2</option>
<option value="">software3</option>
<option value="">--Services--</option>
<option value="">service1</option>
<option value="">service2</option>
<option value="">service3</option>
</select>
I have the above List on my HTML select field.
I want to be able to get only the values --Product--, --Software--, --Services--
So I created an loop to go throw the list of products and used the method startwith to pickup the values starting with "--".
function loadFilter() {
var x = document.getElementById('List');
var i;
var n;
for (i = 0; i < x.length; i++) {
str = x[i].text
var n = str.startsWith('--');
flag = true;
if (n == true) {
alert(x[i].text); // list --Product--, --Software--, --Services--
alert(x[3].text); // prints from the LIST <product1> and not <--Services-->
}
}
}
So when the flag is true, the alert(x[i].text); list correctly the values (--Product--, --Software--, --Services--).
But when I try to get them by their values(index), E.G ..I need to get only (--Services--), so I use x[3].text), but this returns me the whole List values >> and not <--Services-->.

You can use the below code to populate array arr with the list of options having "--".
Then you can use arr[2] to get --Services--.
var arr = [];
[].slice.call(document.querySelectorAll("#List option")).map(function(el){
if (el.text.indexOf("--") === 0) arr.push(el.text);
});
console.log(arr)
console.log(arr[2])
<select name="List" id="List">
<option value="">-Select-</option>
<option value="">--Product--</option>
<option value="">product1</option>
<option value="">product2</option>
<option value="">product3</option>
<option value="">--Software--</option>
<option value="">software1</option>
<option value="">software2</option>
<option value="">software3</option>
<option value="">--Services--</option>
<option value="">service1</option>
<option value="">service2</option>
<option value="">service3</option>
</select>

Here you go:
function loadFilter() {
var element = document.getElementById('List');
var children = element.children;
var filtered = [];
for (var i = 0; i < children.length; i++) {
if (children[i].textContent.startsWith('--')) {
filtered.push(children[i].textContent);
}
}
return filtered;
}
To recap what the function did:
Get the element "List"
Get the children of "List"
Create an array to hold elements that pass the filter
Go through each element and add those with match the specified regex
Return the elements that pass the filter

I'm still not entirely sure what you're trying to do. --Services-- is index 9, not 3. To get --Services-- you need x[9].text
If you want to rearrange the three --xx-- into their own index, you need to push them into a new array, like so:
var output = []
if (n === true) output.push(x[i].text)
console.log(output[2]) // --Services--

You can use simple forEach loop to loop through elements like here, but first you need to create Array from your DOM Node list:
var list = Array.from(x);
list.forEach((value,index)=>{
if (value.text.startsWith('--')){
alert(value.text);
}
});
I've put it up on fiddle so you can check:
https://jsfiddle.net/pegla/qokwarcy/

First of all, you don't seen to be using your flag at all.
If I understood it correctly, you are trying to get --Services-- using x[3].text, but if you count your whole list the element at index [3] is the . You can verify that with the code bellow:
f (n == true) {
alert('index '+ i + ': ' + x[i].text); // list --Product--, --Software--, --Services--
}
You could create a new array containing the filtered options and then access the with the known index:
var filteredArray = [];
f (n == true) {
filteredArray.push(x[i]); //insert the element in the new array.
}
alert(filteredArray[2].text) //print --Service--, the third element of filtered array.
Remember that javascript has zero indexed array, so the first element has index 0, so, in order to acces the third element you'll need the index 2.

May be you want to try using optgroups?
Something like this:
<select name="List" id="List">
<option value="">-Select-</option>
<optgroup label="--Product--">
<option value="">product1</option>
<option value="">product2</option>
<option value="">product3</option>
</optgroup>
<optgroup label="--Software--">
<option value="">software1</option>
<option value="">software2</option>
<option value="">software3</option>
</optgroup>
<optgroup label="--Services--">
<option value="">service1</option>
<option value="">service2</option>
<option value="">service3</option>
</optgroup>
</select>
Then,
var select = document.getElementById('List');
var optgroups = select.getElementsByTagName('optgroup');
console.log(optgroups[2].label);
Will show:
--Services--

try:
function load() {
list = document.getElementById('List');
var data = document.getElementsByTagName('option');
currentCatagory=null;//the current selected catagory
currentvalue=null;
listdata=[];
//for all the options
for(cnt = 0; cnt < data.length; cnt++){
var e = data[cnt].innerHTML;//get option text
if(e.startsWith('-')){//test to make a catagory out of it
if(currentCatagory!=null)//do not concat is listdata is null
listdata=listdata.concat(currentCatagory);
currentCatagory = {"this":e,"listOfItems":[]};//create the catagory
}else if(currentCatagory!=null){//make sure currentCatagory is not null
var l=currentCatagory.listOfItems;//get the Catagory's list
currentCatagory.listOfItems = l.concat(e);//and add e
}
}
listdata=listdata.concat(currentCatagory);//add last catagory
//sets the list to show only catagories
var inner='';
for (i = 0; i < listdata.length; i++) {
inner+=parseOp(listdata[i].this);
}
list.innerHTML=inner;
}
function update(){
//check to make sure everything is loaded
if(typeof list=='undefined'){
load();
}
var inner='';//the new options
var value=list.options[list.selectedIndex].innerHTML;
if(value==currentvalue) return;
if(value.startsWith('-')){//if catagory
if(value.startsWith('--')){//if not -Select-
for (i = 0; i < listdata.length; i++) {//for all catagories
if(value==listdata[i].this){//if it is the current selected catagory then...
currentCatagory=listdata[i];//update the currentCatagory object
inner+=parseOp(listdata[i].this);//parse as option and append
//then append catagory's items
for(item in listdata[i].listOfItems){
inner+=parseOp(listdata[i].listOfItems[item]);
}
}else{//appends the other catagories
inner+=parseOp(listdata[i].this);
}
}
}else{//if it is '-select-' then just append the catagories
for (i = 0; i < listdata.length; i++) {
inner+=parseOp(listdata[i].this);
}
}
//set the new options
list.innerHTML=inner;
}
}
function parseOp(str){
//parse the options
return '<option value="">'+str+'</option>';
}
<select name="List" id="List" onchange="update();">
<option value="">-Select-</option>
<option value="">--Product--</option>
<option value="">product1</option>
<option value="">product2</option>
<option value="">product3</option>
<option value="">--Software--</option>
<option value="">software1</option>
<option value="">software2</option>
<option value="">software3</option>
<option value="">--Services--</option>
<option value="">service1</option>
<option value="">service2</option>
<option value="">service3</option>
</select>
and to set the dropdown box you will have to run load() otherwise load() will only be called after the first change event occurs.

javascript drop down list equal to the same number of textbox

I have one drop-down list that has numbers 1-10 and a proceed button.
What I want is, when the user select a specific number and the user click the proceed button, it should display a number of textboxes equal to the number of selected in the drop-down list.
is it possible to doit with a loop? or any suggestions?

Using addEventListener, you can generate the textboxes as:
function create(param) {
//'use strict';
var i, target = document.getElementById('screens');
target.innerHTML = '';
for (i = 0; i < param; i += 1) {
target.innerHTML += '<input type="text" name="Fname"><br /><br />';
}
}
document.getElementById('createTextboxes').addEventListener('change', function () {
create(this.value);
}, false);
JsFiddle Demo

Here is an option - using jQuery cos its much cooler than just plain JS - first determine the number of textboxes required based on the value of the select list. Then create a string with the required number of textboxes and third - apply that HTMl to the empty div. Note that the reason for building the textboxes as a string and then adding it to the div is that this requires only one alteration to the DOM - doing it on each iteration would require altering the DOM numerous times. Its fine if you don't want to use jQuery - as the other answers demonstrate - all things done in jQ can be done in JS - but its just more fun to use.
$(document).ready(function(){
$('#selection').change(function(){
var num = $(this).val();
var HTML='';
for(i = 0; i < num; i++){
HTML += "<input type='text' name='textBox"+i+"' /><br/>"
}
$('#newDiv').html(HTML);
})
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label for = "selection"> Enter the number of textboxes required</label>
<select id="selection">
<option disabled selected></option>
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
</select>
<hr/>
<div id="newDiv"></div>

Try this... Pure Js and Fast
function creator(){
var tb = document.getElementById("generator").value
var area = document.getElementById("tbArea");
var childcount = area.childNodes.length;
if(childcount != 0)
{ for(var i = childcount-1; i > -1;i--)
{
area.removeChild(area.childNodes[i]);
}
}
for(var i =0; i < tb; i++){
var tbox = document.createElement('input');
document.getElementById("tbArea").appendChild(tbox);
}
}
document.getElementById("generator").onchange = creator;
<select id='generator'>
<option value='1'>1</option>
<option value='2'>2</option>
<option value='3'>3</option>
<option value='4'>4</option>
<option value='5'>5</option>
<option value='6'>6</option>
<option value='7'>7</option>
<option value='8'>8</option>
<option value='9'>9</option>
<option value='10'>10</option>
</select>
<div id='tbArea'></div>

How to get selected values in SumoSelect dropdown?

I am using the SumoSelect dropdown for multiselect options. But i cannot get the selected values array.
Below the sample code :
<script type="text/javascript">
$(document).ready(function () {
window.testSelAll = $('.testSelAll').SumoSelect({okCancelInMulti:true, selectAll:true });
$('.btnOk').on('click', function(){
var obj = [];
$('option:selected').each(function () {
obj.push($(this).index());
alert("Selected Values=="+$(this).val());
});
for (var i = 0; i < obj.length; i++) {
$('.testSelAll')[0].sumo.unSelectItem(obj[i]);
}
});
});
</script>
<select multiple="multiple" placeholder="Share Your Friends" onchange="console.log($(this).children(':selected').length)" class="testSelAll">
<option value="1">Volvo</option>
<option value="2">Saab</option>
<option value="3">Mercedes</option>
<option value="audi">Audi</option>
<option value="bmw">BMW</option>
<option value="porsche">Porche</option>
<option value="ferrari">Ferrari</option>
<option value="mitsubishi">Mitsubishi</option>
</select>

If you want the selected values instead of the text, just change .text() to .val().
If you want to get the array, see below with working example at the bottom.
jQuery
$(document).ready(function() {
$('.testSelAll').SumoSelect({
okCancelInMulti: true,
selectAll: true
});
$('.btnOk').on('click', function() {
var obj = [],
items = '';
$('.testSelAll option:selected').each(function(i) {
obj.push($(this).val());
$('.testSelAll')[0].sumo.unSelectItem(i);
});
for (var i = 0; i < obj.length; i++) {
items += ' ' + obj[i]
};
alert(items);
});
});
HTML
<select multiple="multiple" class="testSelAll">
<option value="car1">Volvo</option>
<option value="car2">Saab</option>
<option value="car3">Mercedes</option>
<option value="car4">Audi</option>
</select>
Working JSFIDDLE

You can get them from underlying hidden select element.
using jquery eg.
$('.select1 option:selected')

I think the cleanest way to do this. Is to take advantage of html5 select element underlying SumoSelect.
HTML
<select multiple="multiple" class="testSelAll" id="multi-select">
<option value="car1">Volvo</option>
<option value="car2">Saab</option>
<option value="car3">Mercedes</option>
<option value="car4">Audi</option>
</select>
Javascript
var values = $('#multi-select').val();
This line will return a string list of the values selected.

Get all select/option lists start by something

In an HTML page i have severals list.
<select name="salut-1358937506000-OK">
<option selected="" value="OK">OK</option>
<option value="OK">NOK</option>
</select>
<select name="salut-1358937582000-OK">
<option selected="" value="OK">OK</option>
<option value="OK">NOK</option>
</select>
...
In javascript, I want to get all select/option list which started by "salut-".
For theses list, i want to compare his name and his selected value.
I know it is possible in jQuery but can't use jquery, only javascript (JSNI with GWT exactly).
Have you an idea?
Thanks!

var selects = document.getElementsByTagName('select');
var sel;
var relevantSelects = [];
for(var z=0; z<selects.length; z++){
sel = selects[z];
if(sel.name.indexOf('salut-') === 0){
relevantSelects.push(sel);
}
}
console.log(relevantSelects);

You can use the getElementsByTagName function to get each SELECT name, for example:
var e = document.getElementsByTagName("select");
for (var i = 0; i < e.length; i++){
var name = e[i].getAttribute("name");
}
Then you can use the following code to get each OPTION for the SELECT, to do any necessary comparisons:
var options = e[i].getElementsByTagName("option")

Changing the selected option of an HTML Select element

In my HTML, I have a <select> with three <option> elements. I want to use jQuery to check each option's value against a Javascript var. If one matches, I want to set the selected attribute of that option. How would I do that?

Vanilla JavaScript
Using plain old JavaScript:
var val = "Fish";
var sel = document.getElementById('sel');
document.getElementById('btn').onclick = function() {
var opts = sel.options;
for (var opt, j = 0; opt = opts[j]; j++) {
if (opt.value == val) {
sel.selectedIndex = j;
break;
}
}
}
<select id="sel">
<option>Cat</option>
<option>Dog</option>
<option>Fish</option>
</select>
<button id="btn">Select Fish</button>
jQuery
But if you really want to use jQuery:
var val = 'Fish';
$('#btn').on('click', function() {
$('#sel').val(val);
});
var val = 'Fish';
$('#btn').on('click', function() {
$('#sel').val(val);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<select id="sel">
<option>Cat</option>
<option>Dog</option>
<option>Fish</option>
</select>
<button id="btn">Select Fish</button>
jQuery - Using Value Attributes
In case your options have value attributes which differ from their text content and you want to select via text content:
<select id="sel">
<option value="1">Cat</option>
<option value="2">Dog</option>
<option value="3">Fish</option>
</select>
<script>
var val = 'Fish';
$('#sel option:contains(' + val + ')').prop({selected: true});
</script>
Demo
But if you do have the above set up and want to select by value using jQuery, you can do as before:
var val = 3;
$('#sel').val(val);
Modern DOM
For the browsers that support document.querySelector and the HTMLOptionElement::selected property, this is a more succinct way of accomplishing this task:
var val = 3;
document.querySelector('#sel [value="' + val + '"]').selected = true;
Demo
Knockout.js
<select data-bind="value: val">
<option value="1">Cat</option>
<option value="2">Dog</option>
<option value="3">Fish</option>
</select>
<script>
var viewModel = {
val: ko.observable()
};
ko.applyBindings(viewModel);
viewModel.val(3);
</script>
Demo
Polymer
<template id="template" is="dom-bind">
<select value="{{ val }}">
<option value="1">Cat</option>
<option value="2">Dog</option>
<option value="3">Fish</option>
</select>
</template>
<script>
template.val = 3;
</script>
Demo
Angular 2
Note: this has not been updated for the final stable release.
<app id="app">
<select [value]="val">
<option value="1">Cat</option>
<option value="2">Dog</option>
<option value="3">Fish</option>
</select>
</app>
<script>
var App = ng.Component({selector: 'app'})
.View({template: app.innerHTML})
.Class({constructor: function() {}});
ng.bootstrap(App).then(function(app) {
app._hostComponent.instance.val = 3;
});
</script>
Demo
Vue 2
<div id="app">
<select v-model="val">
<option value="1">Cat</option>
<option value="2">Dog</option>
<option value="3">Fish</option>
</select>
</div>
<script>
var app = new Vue({
el: '#app',
data: {
val: null,
},
mounted: function() {
this.val = 3;
}
});
</script>
Demo

None of the examples using jquery in here are actually correct as they will leave the select displaying the first entry even though value has been changed.
The right way to select Alaska and have the select show the right item as selected using:
<select id="state">
<option value="AL">Alabama</option>
<option value="AK">Alaska</option>
<option value="AZ">Arizona</option>
</select>
With jquery would be:
$('#state').val('AK').change();

You can change the value of the select element, which changes the selected option to the one with that value, using JavaScript:
document.getElementById('sel').value = 'bike';​​​​​​​​​​
DEMO

Markup
<select id="my_select">
<option value="1">First</option>
<option value="2">Second</option>
<option value="3">Third</option>
</select>
jQuery
var my_value = 2;
$('#my_select option').each(function(){
var $this = $(this); // cache this jQuery object to avoid overhead
if ($this.val() == my_value) { // if this option's value is equal to our value
$this.prop('selected', true); // select this option
return false; // break the loop, no need to look further
}
});
Demo

I want to change the select element's selected option's both value & textContent (what we see) to 'Mango'.
Simplest code that worked is below:
var newValue1 = 'Mango'
var selectElement = document.getElementById('myselectid');
selectElement.options[selectElement.selectedIndex].value = newValue1;
selectElement.options[selectElement.selectedIndex].textContent = newValue1;
Hope that helps someone. Best of luck.
Up vote if this helped you.

I used almost all of the answers posted here but not comfortable with that so i dig one step furter and found easy solution that fits my need and feel worth sharing with you guys.
Instead of iteration all over the options or using JQuery you can do using core JS in simple steps:
Example
<select id="org_list">
<option value="23">IBM</option>
<option value="33">DELL</option>
<option value="25">SONY</option>
<option value="29">HP</option>
</select>
So you must know the value of the option to select.
function selectOrganization(id){
org_list=document.getElementById('org_list');
org_list.selectedIndex=org_list.querySelector('option[value="'+id+'"]').index;
}
How to Use?
selectOrganization(25); //this will select SONY from option List
Your comments are welcome. :) AzmatHunzai.

Test this Demo
Selecting Option based on its value
var vals = [2,'c'];
$('option').each(function(){
var $t = $(this);
for (var n=vals.length; n--; )
if ($t.val() == vals[n]){
$t.prop('selected', true);
return;
}
});
Selecting Option based on its text
var vals = ['Two','CCC']; // what we're looking for is different
$('option').each(function(){
var $t = $(this);
for (var n=vals.length; n--; )
if ($t.text() == vals[n]){ // method used is different
$t.prop('selected', true);
return;
}
});
Supporting HTML
<select>
<option value=""></option>
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
<select>
<option value=""></option>
<option value="a">AAA</option>
<option value="b">BBB</option>
<option value="c">CCC</option>
</select>

Excellent answers - here's the D3 version for anyone looking:
<select id="sel">
<option>Cat</option>
<option>Dog</option>
<option>Fish</option>
</select>
<script>
d3.select('#sel').property('value', 'Fish');
</script>

After a lot of searching I tried #kzh on select list where I only know option inner text not value attribute,
this code based on select answer I used it to change select option according to current page urlon this format
http://www.example.com/index.php?u=Steve
<select id="sel">
<option>Joe</option>
<option>Steve</option>
<option>Jack</option>
</select>
<script>
var val = window.location.href.split('u=')[1]; // to filter ?u= query
var sel = document.getElementById('sel');
var opts = sel.options;
for(var opt, j = 0; opt = opts[j]; j++) {
// search are based on text inside option Attr
if(opt.text == val) {
sel.selectedIndex = j;
break;
}
}
</script>
This will keeps url parameters shown as selected to make it more user friendly and the visitor knows what page or profile he is currently viewing .

You just write the code
var theVal = 1;
$('#variable_id').val(theVal).trigger('change');

I used this after updating a register and changed the state of request via ajax, then I do a query with the new state in the same script and put it in the select tag element new state to update the view.
var objSel = document.getElementById("selectObj");
objSel.selectedIndex = elementSelected;
I hope this is useful.

selectElement is a html <select> element.
Increment the value:
selectElement.selectedIndex++
Decrement the value:
selectElement.selectedIndex--

var accHos = document.getElementById("accHos");
function showName(obj) {
accHos.selectedIndex = obj.selectedIndex;
}
div {
color: coral;
}
select {
margin-left: 20px;
margin-bottom: 8px;
min-width: 120px;
}
<div>Select Account Number:</div>
<select id="accNos" name="" onchange="showName(this);">
<option value="">Select Account</option>
<option value="">1052021</option>
<option value="">2052021</option>
<option value="">3052021</option>
<option value="">4052021</option>
<option value="">5052021</option>
</select>
<div>Account Holder Name:</div>
<select id="accHos" name="" disabled>
<option value="">--Name--</option>
<option value="">Suhan</option>
<option value="">Cesur</option>
<option value="">Hopper</option>
<option value="">Rachel</option>
<option value="">Arya</option>
</select>
<!-- Just for my referece -->

Slightly neater Vanilla.JS version. Assuming you've already fixed nodeList missing .forEach():
NodeList.prototype.forEach = Array.prototype.forEach
Just:
var requiredValue = 'i-50332a31',
selectBox = document.querySelector('select')
selectBox.childNodes.forEach(function(element, index){
if ( element.value === requiredValue ) {
selectBox.selectedIndex = index
}
})