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how to fill two or more selects with the same option elements

I'd like to add the same options elements to more than one select, using one JavaScript function.
<select id="select1" name="select1"></select>
<select id="select2" name="select2"></select>
I want selects become:
<select id="select1" name="select1">
<option value="0">Txt1</option>
<option value="1">Txt2</option>
<option value="2">Txt3</option>
</select>
<select id="select2" name="select2">
<option value="0">Txt1</option>
<option value="1">Txt2</option>
<option value="2">Txt3</option>
</select>
Here is part of function to fill selects with options:
function window_onload(){
var SpecTxt = new Array("Txt1","Txt2","Txt3");
for(var i=0; i<SpecTxt.length; i++) {
var oOption = document.createElement("OPTION");
oOption.text = SpecTxt[i];
oOption.value=i;
select1.add(oOption); // Option to first SELECT
select2.add(oOption); // Option to second SELECT
}
}
But I've got Internet Explorer Script Error "Invalid argument", result is only one first option in "select1" and no options in "select2". If I remove from function window_onload() the last string select2.add(oOption);, there are no IE errors and "select1" is filled as must be, but "select2" is empty. How is it possible in JS to add the same options to different SELECTs?

Update
The reason why the Demo didn't work for IE is because it doesn't recognize the property .valueAsNumber.
From:
var opts = qty.valueAsNumber;
To:
var opts = parseInt(qty.value, 10);
When you create an option within the loop:
var oOption = document.createElement("OPTION");
That is only one <option> not two <option>s. So that is the reason why:
select1.add(oOption); // Succeeds
select2.add(oOption); // Fails
You can either make 2 <option>s per loop:
var oOption1 = document.createElement("OPTION");
var oOption2 = document.createElement("OPTION");
OR try cloneNode(). See Demo below:
Demo
// See HTMLFormControlsCollection
var form = document.forms.ui;
var ui = form.elements;
var qty = ui.qty0;
var s0 = ui.sel0;
var s1 = ui.sel1;
// Declare a counter variable outside of loop
var cnt = 0;
// Add event handler to the change event of the input
qty.onchange = addOpt;
/* Get the value of user input as a number
|| within the for loop...
|| create an <option> tag...
|| add text to it with an incremented offset...
|| add a incremented value to it...
|| then clone it...
|| add original <option> to the first <select>...
|| add duplicate <option> to the second <select>
*/
function addOpt(e) {
var opts = parseInt(qty.value, 10);
for (let i = 0; i < opts; i++) {
var opt = document.createElement('option');
opt.text = 'Txt' + (cnt + 1);
opt.value = cnt;
var dupe = opt.cloneNode(true);
s0.add(opt);
s1.add(dupe);
cnt++;
}
}
input,
select,
option {
font: inherit
}
input {
width: 4ch;
}
<form id='ui'>
<fieldset>
<legend>Enter a number in the first form field</legend>
<input id='qty0' name='qty0' type='number' min='0' max='30'>
<select id="sel0" name="sel0"></select>
<select id="sel1" name="sel1"></select>
</fieldset>
</form>
Reference
HTMLFormControlsCollection

How to populate select options from an array based on a select value?

Trying to get my second select element's options to populate from an array based on the value of the first select element. I can't seem to understand why it only populates the items from the array of the first select element. I know the appendChild is causing the items to keep tacking on at the need, but I've tried to clear the variables, but it seems the option elements that were created stay.
Any help would be great, thanks!
<select id="makeSelect" onChange="modelAppend()">
<option value="merc">Mercedes</option>
<option value="audi">Audi</option>
<option value="bmw">BMW</option>
</select>
<select id="modelSelect">
</select>
<script>
var audiModels = ["TT", "R8", "A4", "A6"]; //audimodels
var mercModels = ["C230", "B28", "LTX",]; //mercmodels
var bmwModels = ["328", "355", "458i",]; //bmwmodels
var selectedMake = document.getElementById("makeSelect"); //grabs the make select
var selectedModel = document.getElementById("modelSelect"); //grabs the model select
var appendedModel = window[selectedMake.value + "Models"]; // appends "Models" to selectedMake.value and converts string into variable
function modelAppend() {
for (var i = 0; i < appendedModel.length; i ++) { // counts items in model array
var models = appendedModel[i]; // // sets "models" to count of model array
var modelOptions = document.createElement("option"); //create the <option> tag
modelOptions.textContent = models; // assigns text to option
modelOptions.value = models; // assigns value to option
selectedModel.appendChild(modelOptions); //appeneds option tag with text and value to "modelSelect" element
}
}
</script>

This line is fishy:
var appendedModel = window[selectedMake.value + "Models"];
You need to get the element when the value has changed, not on page load. Then you need to remove the options on change too, or you will get a very long list if the user selects multiple times. Use an object to store the arrays, that makes it much easier to access them later. Also better use an event listener instead of inline js (though that's not the main problem here).
Try below code:
let models = {
audiModels: ["TT", "R8", "A4", "A6"],
mercModels: ["C230", "B28", "LTX"],
bmwModels: ["328", "355", "458i"]
}
document.getElementById('makeSelect').addEventListener('change', e => {
let el = e.target;
let val = el.value + 'Models';
let appendTo = document.getElementById('modelSelect');
Array.from(appendTo.getElementsByTagName('option')).forEach(c => appendTo.removeChild(c));
if (!models[val] || !Array.isArray(models[val])) {
appendTo.style.display = 'none';
return;
}
models[val].forEach(m => {
let opt = document.createElement('option');
opt.textContent = opt.value = m;
appendTo.appendChild(opt);
});
appendTo.style.display = '';
});
<select id="makeSelect">
<option value=""></option>
<option value="merc">Mercedes</option>
<option value="audi">Audi</option>
<option value="bmw">BMW</option>
</select>
<select id="modelSelect" style="display:none">
</select>

HTML Select control behavior

I am trying to make an HTML Select control display a different set of strings when clicked (or opened) than what is displayed after an item is selected. For example, when opened I want to see "one", two", "three" displayed as choices. But if the user selects two, I want "2" to be displayed as the selected item. My onclick handler reloads the Select options list with the long version of the strings and the onchange handler repopulates the control with the short strings and then re-selects the selected item. This works in Firefox, but not in IE, Safari nor Chrome. It's been almost 10 years since I last had the pleasure of coding in JavaScript. Any help would be appreciated. Here's my code:
var selectedIndex = -1;
function onChanged() {
//once selected, replace verbose with terse forms
var myList = document.getElementById("myList");
selectedIndex = myList.selectedIndex;
var optionArray = ["One|1", "Two|2", "Three|3"];
myList.options.length = 0;
for (var option in optionArray) {
var pair = optionArray[option].split("|");
var newOption = document.createElement("option");
newOption.value = pair[1];
newOption.innerHTML = pair[1];
myList.options.add(newOption);
}
myList.selectedIndex = selectedIndex;
}
function onClicked() {
var myList = document.getElementById("myList");
var optionArray = ["1|One", "2|Two", "3|Three"];
myList.options.length = 0;
for (var option in optionArray) {
var pair = optionArray[option].split("|");
var newOption = document.createElement("option");
newOption.value = pair[1];
newOption.innerHTML = pair[1];
myList.options.add(newOption);
}
if (selectedIndex > -1)
myList.selectedIndex = selectedIndex;
}
<select id="myList" onchange="onChanged()" onclick="onClicked()">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>

An alternate approach would be to have each option store the full version of the text, and only change the displayed text of the selected item to the abbreviated version upon selection.
(function() {
var valueMap = {
"1": "One (1)",
"2": "Two (2)",
"11": "Eleven (11)",
"ITAR": "International Traffic in Arms Regulation (ITAR)",
"ACA": "Affordable Care Act (ACA)",
"FUBAR": "Fluffed Up Beyond All Recognition (FUBAR)"
};
var myList = document.getElementById("myList");
for (var prop in valueMap) { // populate the dropdown from our object
var opt = document.createElement("option");
opt.value = prop;
opt.text = valueMap[prop];
myList.add(opt);
}
myList.selectedIndex = -1; // nothing selected by default
myList.addEventListener("change", function() {
this.options[this.selectedIndex].text = this.options[this.selectedIndex].value;
this.blur();
});
myList.addEventListener("mousedown", function() {
if (this.selectedIndex > -1) {
var newValue = valueMap[this.options[this.selectedIndex].value];
if (this.options[this.selectedIndex].text !== newValue) {
this.options[this.selectedIndex].text = newValue;
}
}
});
})();
<select id="myList" style="width:6em"></select>
This gets you most of the way there, but still has the annoying problem that #hopkins-matt alluded to; namely that if the user opens the drop-down list and either selects the already selected item or moves off of the list without selecting anything, the selection will retain the long version of the text.
The other downside to this approach is that you need to specify the select element's width to keep it from expanding to the maximum length of its hidden option elements.

It's a timing issue.
Change:
<select id="myList" onchange="onChanged()" onclick="onClicked()">
to:
<select id="myList" onchange="onChanged()" onmousedown="onClicked()">
If the user opens the list and moves off the list without clicking, the list will not revert to original unless you call onChanged() on onmouseout as well.
<select id="myList" onchange="onChanged()" onmousedown="onClicked()" onmouseout="onChanged()">
Update: To achieve the best cross browser (onfocus is required for FF, but breaks IE) support without browser sniffing us this combination:
<select id="myList" onchange="onChanged()" onblur="onChanged()" onfocus="onClicked()" onmousedown="onClicked()">
This will also correct the second selection of the same event, but only after the user clicks away from the element.
Update:
Solved... I think.
I rewrote the function you were using to change the options. IE was not firing onchange due to you removing all the option elements and adding new option elements. Which was causing IE to not be able to reference if the user had changed the selection index. The function now just modifies the value and innerHTML of the current option elements. I am using browser sniffing to eliminate the onmouseout call for FF. FireFox was calling onmouseout if you moved the cursor to the dropdown menu. This does cause a side effect in FF. If the user selects the same option in FF, the options do not return to the original state until the onblur is fired.
Demo: http://jsfiddle.net/hopkins_matt/3m1syk6c/
JS:
function changeOptions() {
var selectedIndex = -1;
var click = 0;
var myList = document.getElementById("myList");
var optionArray = ["One|1", "Two|2", "Three|3"];
var fireFox = /Firefox/i.test(navigator.userAgent);
console.log(fireFox);
if (fireFox == false) {
myList.onmouseout=function(){changeList(false)};
}
myList.onblur=function(){changeList(false)};
myList.onchange=function(){changeList(false)};
myList.onmousedown=function(){changeList(true)};
function changeList(listOpen) {
var isListOpen = listOpen;
if (isListOpen == true) {
for (i = 0; i < myList.options.length; i++) {
var pair = optionArray[i].split("|");
myList.options[i].value = pair[0];
myList.options[i].innerHTML = pair[0];
}
}
if (isListOpen == false) {
for (i = 0; i < myList.options.length; i++) {
var pair = optionArray[i].split("|");
myList.options[i].value = pair[1];
myList.options[i].innerHTML = pair[1];
}
}
}
}
changeOptions();
HTML:
<select id="myList">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>

How to get focus for selected values when multiselect combo is used

I'm using a multiselect combobox, i select few values from the combobox and save the selected values to db. when i reopen the page, i need the focus to be placed on the values which was selected and saved.
function getSelectedValues() {
var from = document.getElementById("309127");
var to;
var v = from.options.length;
var selectedValues = "";
for (var i = 0; i < v; i++) {
if (from.options[i] && from.options[i].selected) {
var CVal = from.options[i].value;
var CText = from.options[i].text;
if (selectedValues == "") {
selectedValues = CVal;
}
else {
selectedValues = selectedValues + "~" + CVal;
}
}
}
return selectedValues;
}
this is the javascript function i used to save the selected values in db.
can anybody help me out on how to get the focus back on selected items ?
thank you

To set the focus with javascript you can use
document.getElementById("309127").focus();
For your question I'm assuming you send the values to a PHP page or something similar to update the database. If so your problem will be getting the selected values when you return to your page. Two suggestions:
Use ajax to update the database so you dont need to exit the page,
Pass the selected values back to your page through GET or similar and set the focus on page load.
EDIT: -------------
For example if you pass the values through GET like (www.example.com?param1=three)
You can use javascript to select that value on load:
<html>
<body onload="load()">
<select id="example">
<option value="one"> one </option>
<option value="two"> two </option>
<option value="three"> three </option>
</select>
</body>
<script>
function load(){
var param1 = getParameterByName("param1");
var selected = document.getElementById('example');
var opts = selected.options.length;
for (var i=0; i<opts; i++){
if (selected.options[i].value == param1){
selected.options[i].selected = true;
break;
}
}
}
function getParameterByName(name)
{
name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]");
var regexS = "[\\?&]" + name + "=([^&#]*)";
var regex = new RegExp(regexS);
var results = regex.exec(window.location.search);
if(results == null)
return "";
else
return decodeURIComponent(results[1].replace(/\+/g, " "));
}
</script>
</html>

try var from = document.getElementById("309127");from.focus();

How would I dynamically create input boxes on the fly?

I want to use the value of a HTML dropdown box and create that number of input boxes underneath. I'm hoping I can achieve this on the fly. Also if the value changes it should add or remove appropriately.
What programming language would I need to do this in? I'm using PHP for the overall website.

Here is an example that uses jQuery to achieve your goals:
Assume you have following html:
<div>
<select id="input_count">
<option value="1">1 input</option>
<option value="2">2 inputs</option>
<option value="3">3 inputs</option>
</select>
<div>
<div id="inputs"> </div>
And this is the js code for your task:
$('#input_count').change(function() {
var selectObj = $(this);
var selectedOption = selectObj.find(":selected");
var selectedValue = selectedOption.val();
var targetDiv = $("#inputs");
targetDiv.html("");
for(var i = 0; i < selectedValue; i++) {
targetDiv.append($("<input />"));
}
});
You can simplify this code as follows:
$('#input_count').change(function() {
var selectedValue = $(this).val();
var targetDiv = $("#inputs").html("");
for(var i = 0; i < selectedValue; i++) {
targetDiv.append($("<input />"));
}
});
Here is a working fiddle example: http://jsfiddle.net/melih/VnRBm/
You can read more about jQuery: http://jquery.com/

I would go for jQuery.
To start with look at change(), empty() and append()
http://api.jquery.com/change/
http://api.jquery.com/empty/
http://api.jquery.com/append/

Doing it in javascript is quite easy. Assuming you've got a number and an html element where to insert. You can obtain the parent html element by using document.getElementById or other similar methods. The method assumes the only children of the parentElement is going to be these input boxes. Here's some sample code:
function addInput = function( number, parentElement ) {
// clear all previous children
parentElement.innerHtml = "";
for (var i = 0; i < number; i++) {
var inputEl = document.createElement('input');
inputEl['type'] = 'text';
// set other styles here
parentElement.appendChild(inputEl);
}
}
for the select change event, look here: javascript select input event

you would most likely use javascript(which is what jquery is), here is an example to show you how it can be done to get you on your way
<select name="s" onchange="addTxtInputs(this)" onkeyup="addTxtInputs(this)">
<option value="0">Add</option>
<option value="1">1</option>
<option value="3">3</option>
<option value="7">7</option>
</select>
<div id="inputPlaceHolder"></div>
javascript to dynamically create a selected number of inputs on the fly, based on Mutahhir answer
<script>
function addTxtInputs(o){
var n = o.value; // holds the value from the selected option (dropdown)
var p = document.getElementById("inputPlaceHolder"); // this is to get the placeholder element
p.innerHTML = ""; // clears the contents of the place holder each time the select option is chosen.
// loop to create the number of inputs based apon `n`(selected value)
for (var i=0; i < n; i++) {
var odiv = document.createElement("div"); //create a div so each input can have there own line
var inpt = document.createElement("input");
inpt['type'] = "text"; // the input type is text
inpt['id'] = "someInputId_" + i; // set a id for optional reference
inpt['name'] = "someInputName_" + i; // an unique name for each of the inputs
odiv.appendChild(inpt); // append the each input to a div
p.appendChild(odiv); // append the div and inputs to the placeholder (inputPlaceHolder)
}
}
</script>