We Keep Coding

Get selected optgroup in JavaScript

I have the below select tag with two optgroup.
<select id="linkSelector" class="form-control" onchange="linkDropDown();">
<optgroup label="Input">
<option value="default">Road type</option>
<option value="lanes">Lanes</option>
<option value="length">Length</option>
<option value="speed">Speed</option>
</optgroup>
<optgroup label="Ouput">
<option value="congestion">Congestion</option>
<option value="speed_output">Speed</option>
<option value="travel_time">Travel Time</option>
</optgroup>
</select>
I would like to execute myFuncton() depending on the selected optgroup.
For example if one of the dropdown value belong to <optgroup label="Input">, then execute myFunction().
I tried this:
var linkSelector = document.getElementById('linkSelector')
opt = linkSelector.getElementsByTagName('optgroup')
if (opt[0].label =='Input'){
myFunction()
}

One way to go about this, would be to get the selected option for the select field, then find out it's parent's label.
var label = document.getElementById('linkSelector').selectedOptions[0].parentElement.label;
if (label === "Input") {
myFunction();
}

How to show/hide items from a select list based on another selection

In JavaScript, how to show/hide items from a select list based on another selected option that contain a certain word or words?
I am very new to JavaScript, so any help would be appreciated.
There are two drop-downs: "group" and "alph".
<select name="group">
<option value="Angry (Two)">Angry (Two)</option>
<option value="Happy (Two)">Happy (Two)</option>
<option value="Sad">Sad</option>
<option value="Tired (One)">Tired (One)</option>
</select>
<select name="alph">
<option value="ABC">ABC</option>
<option value="ABC-1">ABC-1</option>
<option value="ABC-2">ABC-2</option>
<option value="DEF">DEF</option>
<option value="DEF-1">DEF-1</option>
<option value="DEF-2">DEF-2</option>
<option value="DEF-3">DEF-3</option>
</select>
Without IDs, for the first dropdown (name group), if the selected value contains " (Two)", then the list will only show:
<select name="alph">
<option value="ABC-2">ABC-2</option>
<option value="DEF-2">DEF-2</option>
</select>
If the user changes selection, and the selected value contains " (One)", then the list will only show:
<select name="alph">
<option value="ABC-1">ABC-1</option>
<option value="DEF-1">DEF-1</option>
</select>
If the user changes selection, and the selected value does not contain neither " (One)" or " (Two)", then the list will show:
<select name="alph">
<option value="ABC">ABC</option>
<option value="DEF">DEF</option>
<option value="DEF-3">DEF-3</option>
</select>
Note: I am not able to add IDs or attributes. I can only access the name of the select and the value.

Use data-* to create groups, then use a querySelector to get all the options and test if they are apart of the group or not. If they are apart of the group show them otherwise hide them.
// The main group
let groups = document.querySelector('select[name=group]')
// Add a change event
groups.addEventListener('change', (e) => {
// Get the currently selected Group
let current = e.target.options[e.target.selectedIndex]
// Get the data-group number
let group = current.getAttribute('data-group')
// Get all the items from the second dropdown
let opts = Array.from(document.querySelectorAll('select[name=alph]>option'))
// Hide items that are not appart of the group
opts.forEach(itm => itm.style.display = itm.getAttribute('data-group') == group || !itm.getAttribute('data-group') ? 'initial' : 'none')
// Reset the the selection
document.querySelector('select[name=alph]').selectedIndex = 0
})
/* Hide option two items by default */
select[name=alph]>option[data-group]{display:none;}
<select name="group">
<option>Select One...</option>
<option data-group="1" value="Angry (Two)">Angry (Two)</option>
<option data-group="2" value="Happy (Two)">Happy (Two)</option>
<option data-group="3" value="Sad">Sad</option>
<option data-group="4" value="Tired (One)">Tired (One)</option>
</select>
<select name="alph">
<option>Select One...</option>
<option data-group="1" value="ABC">ABC</option>
<option data-group="1" value="ABC-1">ABC-1</option>
<option data-group="2" value="ABC-2">ABC-2</option>
<option data-group="2" value="DEF">DEF</option>
<option data-group="3" value="DEF-1">DEF-1</option>
<option data-group="3" value="DEF-2">DEF-2</option>
<option data-group="4" value="DEF-3">DEF-3</option>
</select>

HTML select option VALUE calculate

I am trying to make a simple "registry book" from a select HTML
The idea is 3 selecting options click confirm and based on the selected options make a price with a math formula or (don't know what is ) an array (in the sense of a table of like every var there) add a Hour:Minute from machine and place it in a paragraph.
It will work. (just learning HTML and CSS)
Math would be select2 * select3 with one exception in the case of [select2(option1 and option2) * select3 = samevalue)
With that aside can someone post a modular simplistic type of code that would Help.
For those who need to read some more:(copy&paste* - *Sorry for indentation)
document.getElementById("Confirm").onClick = function() {
var entry = ""
document.getElementById("Televizor").onChange = function() {
if (this.selectedIndex !== 0) {
entry += this.value;
}
};
document.getElementById("Controllere").onChange = function() {
if (this.selectedIndex !== 0) {
entry += this.value;
}
};
document.getElementById("Timp").onChange = function() {
if (this.selectedIndex !== 0) {
entry += this.value;
}
};
document.getElementById("Table").innerHTML = "<br> " + entry + Date();
var entry = ""
}
<h2>TV-uri</h2>
<button type="button" onclick="document.getElementById('demo').innerHTML = Date()">Date & Time.</button>
<p id="demo">Dunno</p>
<div class="container">
<select id="Televizoare">
<option value="0">Televizoare</option>
<option value="1">Tv 1</option>
<option value="2">Tv 2</option>
<option value="3">TV 3</option>
<option value="4">Tv 4</option>
<option value="5">TV 5</option>
<option value="6">Tv 6</option>
<option value="7">TV 7</option>
</select>
<select id="Controller">
<option value="0">Controllere</option>
<option value="1c">1 Controller</option>
<option value="2c">2 Controllere</option>
<option value="3c">3 Controllere</option>
<option value="4c">4 Controllere</option>
</select>
<select id="Timp">
<option value="0">Timp</option>
<option value="1h">1 ora</option>
<option value="1h2">1 ora 30 minute</option>
<option value="2h">2 ore</option>
<option value="2h2">2 ore 30 minute</option>
<option value="3h">3 ore</option>
</select>
<button id="Confirm" onclick="Confrim)">Confirm</button>
</div>
<p id="Table"></p>

Well, you could start off by making sure the spelling and capitalization of your IDs and function names match.
Also, you should create some form of a validation method to check if all the fields are valid before proceeding to the calculation method.
Not sure what you are multiplying, but if you can at least get the valuse from the form fields, that's half the battle.
You should also enclose all your fields within a form object so you can natively interact with the form in a traditional HTML fashion.
// Define the confirm clicke listener for the Confirm button.
function confirm() {
// Grab all the fields and apply them to a map.
var fields = {
'Televizoare' : document.getElementById('Televizoare'),
'Controllere' : document.getElementById('Controllere'),
'Timp' : document.getElementById('Timp')
};
// Determine if the user selected an option for all fields.
var isValid = doValidation(fields);
if (!isValid) {
document.getElementById("Table").innerHTML = 'Please provide all fields!';
return;
}
// Create listeners ???
fields["Televizoare"].onChange = function(e) { };
fields["Controllere"].onChange = function(e) { };
fields["Timp"].onChange = function(e) { };
// Set the value of the paragraph to the selected values.
document.getElementById("Table").innerHTML = Object.keys(fields)
.map(field => fields[field].value)
.join(' — ');
}
// Validation function to check if ALL fields have options selected other than 0.
function doValidation(fields) {
return [].every.call(Object.keys(fields), field => fields[field].selectedIndex !== 0);
}
<h2>TV-uri</h2>
<button type="button" onclick="document.getElementById('demo').innerHTML = Date()">Date & Time.</button>
<p id="demo">Dunno</p>
<div class="container">
<select id="Televizoare">
<option value="0">Televizoare</option>
<option value="1">Tv 1</option>
<option value="2">Tv 2</option>
<option value="3">TV 3</option>
<option value="4">Tv 4</option>
<option value="5">TV 5</option>
<option value="6">Tv 6</option>
<option value="7">TV 7</option>
</select>
<select id="Controllere">
<option value="0">Controllere</option>
<option value="1c">1 Controllere</option>
<option value="2c">2 Controllere</option>
<option value="3c">3 Controllere</option>
<option value="4c">4 Controllere</option>
</select>
<select id="Timp">
<option value="0">Timp</option>
<option value="1h">1 ora</option>
<option value="1h2">1 ora 30 minute</option>
<option value="2h">2 ore</option>
<option value="2h2">2 ore 30 minute</option>
<option value="3h">3 ore</option>
</select>
<button id="Confirm" onclick="confirm()">Confirm</button>
</div>
<p id="Table"></p>

How can maintain as selected the second option in a drop down with random values?

I want to always maintain how to select the second option for its drop downs. The point here is that the value is random:
MyBrowser.document.getElementById("multipleCat_1").Value = "RANDOMVALUE"
How do I select the second option in a drop down menu?
HTML:
<select id="multipleCat_1">
<option value="-1">Select</option>
<option value="RANDOMVALUE">Second Option"</option>
</select>

You can use selectedIndex as below:
document.querySelectorAll('#multipleCat_1 > option')[1].value = 'Got you!';
document.getElementById('multipleCat_1').selectedIndex = 1
console.log(document.getElementById('multipleCat_1').value)
<select id="multipleCat_1">
<option value="-1">Select</option>
<option value="RANDOMVALUE">Second Option"</option>
</select>

<select id="multipleCat_1">
<option value="A">AAA</option>
<option value="B">BBB</option>
<option value="C">CCC</option>
</select>
var options = document.querySelectorAll('#multipleCat_1 > option');
document.getElementById('multipleCat_1').value = options[1].value;

Populate textbox based on Dropdown selection - JavaScript

I have a little question as I'm very new to JavaScript. I've made a dropdown containing various counties, and based on which county is selected, I want a specific email-address to populate a text field. I'm working with the following HTML form:
<div
<br>
Email:
<br>
<input type="text" id="email" readonly=>
</div>
<div>
<br>
Counties:
<br>
<select id="counties">
<option value="Choose One">Choose One</option>
<option value="Charlotte">Charlotte</option>
<option value="Collier">Collier</option>
<option value="Hillsborough">Hillsborough</option>
<option value="Lee">Lee</option>
<option value="Manatee">Manatee</option>
<option value="Pasco">Pasco</option>
<option value="Pinellas">Pinellas</option>
<option value="Polk">Polk</option>
<option value="Sarasota">Sarasota</option>
<option value="Brevard">Brevard</option>
<option value="Broward">Broward</option>
<option value="Indian River">Indian River</option>
<option value="Martin">Martin</option>
<option value="Miami-Dade">Miami-Dade</option>
<option value="Monroe">Monroe</option>
<option value="Palm Beach">Palm Beach</option>
<option value="St Lucie">St Lucie</option>
</select>
</div>
For the first 9 counties; I'd like them to go to "first#email.com
And for the remaining 8 counties; I'd like them to go to "second#email.com
I'm looking for some insight in how to add a value to the counties, and based on that value (Choose One = 0, first nine counties = 1, remaining eight = 2) I'd like to populate the text field with id="email" with the respective email.
How could I go about setting this up in JavaScript? Thanks in advance.

You can do it with custom attribute. See this fiddle: https://jsfiddle.net/y2t0utk7/
Html
<div>
Email:
<br>
<input type="text" id="email" />
</div>
<div>
<br>
Counties:
<br>
<select id="counties" onChange="return setMail()">
<option data-mail="0" value="Choose One">Choose One</option>
<option data-mail="1" value="Charlotte">Charlotte</option>
<option data-mail="1" value="Collier">Collier</option>
<option data-mail="1" value="Hillsborough">Hillsborough</option>
<option data-mail="1" value="Lee">Lee</option>
<option data-mail="1" value="Manatee">Manatee</option>
<option data-mail="1" value="Pasco">Pasco</option>
<option data-mail="1" value="Pinellas">Pinellas</option>
<option data-mail="1" value="Polk">Polk</option>
<option data-mail="1" value="Sarasota">Sarasota</option>
<option data-mail="2" value="Brevard">Brevard</option>
<option data-mail="2" value="Broward">Broward</option>
<option data-mail="2" value="Indian River">Indian River</option>
<option data-mail="2" value="Martin">Martin</option>
<option data-mail="2" value="Miami-Dade">Miami-Dade</option>
<option data-mail="2" value="Monroe">Monroe</option>
<option data-mail="2" value="Palm Beach">Palm Beach</option>
<option data-mail="2" value="St Lucie">St Lucie</option>
</select>
</div>
JS
function setMail(){
// find the dropdown
var ddl = document.getElementById("counties");
// find the selected option
var selectedOption = ddl.options[ddl.selectedIndex];
// find the attribute value
var mailValue = selectedOption.getAttribute("data-mail");
// find the textbox
var textBox = document.getElementById("email");
// set the textbox value
if(mailValue=="1"){
textBox.value = "first#email.com";
}
else if(mailValue=="2"){
textBox.value = "second#email.com";
}
}

Since you said you are new in javascript, let's use a pure javascript way to do it.
You can add an onChange to the select HTML tag and the function you passed in will be triggered every time you change its value.
Inside the function, you can base on the value of the selection, to decide what is the new value for the email box, using switch, if statement etc..
To do what you want, you can use integer be the value as you mentioned.
HTML:
<select id="counties" onchange="func()">
Javascript:
function func(){
var dropdown = document.getElementById("counties");
var selection = dropdown.value;
console.log(selection);
var emailTextBox = document.getElementById("email");
// assign the email address here based on your need.
emailTextBox.value = selection;
}
Demo