Develop Reference

How to disable select dropdown if it has one option?

Im wondering how to disable the third dropdown in case it didnt have any options after filtering (Excluding the Select option placeholder option).
I guess that adding a if statment like if and $select3.length could solve the issue but dont know how to implement that along with the filtering in my code since im very new to javascript.
<select name="select1" id="select1">
<option value="" disabled selected>Select your option</option>
<option value="1" option-id="1">Sitzen </option>
<option value="2" option-id="2">Schlafen</option>
<option value="3" option-id="3">Reisen</option>
</select>
<select name="select2" id="select2" disabled>
<option value="a" disabled selected option-id="a">Select your option</option>
<option value="1" option-id="1">Comfort Cushion</option>
<option value="2" option-id="1">Freilagerungssitzkissen</option>
<option value="3" option-id="1">Rückenkissen</option>
<option value="4" option-id="1">Sitzkissen zum Druckmanagement</option>
<option value="5" option-id="1">Wedge Cushion</option>
<option value="6" option-id="1">Wedge Pillow</option>
<option value="7" option-id="2">Comfort Pillow</option>
<option value="8" option-id="2">Dreamy Cushion</option>
<option value="9" option-id="2">Kniekissen</option>
<option value="10" option-id="3">Reise Nackenkissen</option>
</select>
<select name="select3" id="select3" disabled>
<option value="a" disabled selected option-id="a">Select your option</option>
<option value="2" option-id="2" >Standard</option>
<option value="3" option-id="2" >Large</option>
<option value="1" option-id="3" >Small</option>
<option value="2" option-id="3" >Standard</option>
<option value="2" option-id="4" >Standard</option>
<option value="3" option-id="4" >Large</option>
</select>
var $select1 = $( '#select1' ),
$select2 = $( '#select2' ),
$select3 = $( '#select3' ), // I added that line but not sure if its correct
$options_a = $select2.find( 'option' ),
$options_b = $select3.find( 'option' ); // I added that line but not sure if its correct
$select1.on( 'change', function() {
$select2.prop("disabled", false);
$select2.html( $options_a.filter(function () {
return $(this).attr('option-id') === $select1.val() ||
$(this).attr('option-id') === "a"
}))
$select2.val('a')
$select3.val('a')
} )
// I added the next lines for select3 but not sure if they are correct
$select2.on( 'change', function() {
$select3.prop("disabled", false);
$select3.html( $options_b.filter(function () {
return $(this).attr('option-id') === $select2.val() ||
$(this).attr('option-id') === "a"
}));
$select3.val('a')
} )
https://jsfiddle.net/arabtornado/bkm25otw/46/

To achieve this you can set the disabled property on $select3 depending on the number of option elements within it. To do that you can add this line within the change event handler for $select2:
$select3.prop('disabled', $select3.find('option').length == 1);
Note that it's disabled when there's only 1 element, as you always have the 'Select your option' default.
Also worth noting is that option-id is a non-standard attribute, which will mean your HTML is invalid. I would suggest using data attributes instead to maintain validity.
var $select1 = $('#select1'),
$select2 = $('#select2'),
$select3 = $('#select3'),
$options_a = $select2.find('option'),
$options_b = $select3.find('option');
$select1.on('change', function() {
$select2.prop("disabled", false).html($options_a.filter(function() {
return $(this).data('option-id') === parseInt($select1.val(), 10) || $(this).data('option-id') === "a"
})).val('a')
$select3.val('a')
})
$select2.on('change', function() {
$select3.html($options_b.filter(function() {
return $(this).data('option-id') === parseInt($select2.val(), 10) || $(this).data('option-id') === "a"
}));
$select3.prop('disabled', $select3.find('option').length == 1).val('a')
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<select name="select1" id="select1">
<option value="" disabled selected>Select your option</option>
<option value="1" data-option-id="1">Sitzen </option>
<option value="2" data-option-id="2">Schlafen</option>
<option value="3" data-option-id="3">Reisen</option>
</select>
<select name="select2" id="select2" disabled>
<option value="a" disabled selected data-option-id="a">Select your option</option>
<option value="1" data-option-id="1">Comfort Cushion</option>
<option value="2" data-option-id="1">Freilagerungssitzkissen</option>
<option value="3" data-option-id="1">Rückenkissen</option>
<option value="4" data-option-id="1">Sitzkissen zum Druckmanagement</option>
<option value="5" data-option-id="1">Wedge Cushion</option>
<option value="6" data-option-id="1">Wedge Pillow</option>
<option value="7" data-option-id="2">Comfort Pillow</option>
<option value="8" data-option-id="2">Dreamy Cushion</option>
<option value="9" data-option-id="2">Kniekissen</option>
<option value="10" data-option-id="3">Reise Nackenkissen</option>
</select>
<select name="select3" id="select3" disabled>
<option value="a" disabled selected data-option-id="a">Select your option</option>
<option value="2" data-option-id="2">Standard</option>
<option value="3" data-option-id="2">Large</option>
<option value="1" data-option-id="3">Small</option>
<option value="2" data-option-id="3">Standard</option>
<option value="2" data-option-id="4">Standard</option>
<option value="3" data-option-id="4">Large</option>
</select>

JS autocalculate multiple fields for total

I have looked at multiple examples of js being used to auto calculate the total but haven't found any applicable for me which has fields calculating different numbers to be combined to create a total. Here is my code below so you can understand more.
<html>
<head>
<meta charset="utf-8">
<title>Calculator</title>
<script language="javascript">
function Calc(className){
var elements = document.getElementsByClassName(className);
var totalCost = 0;
for(var i = 0; i < elements.length; i++){
totalCost += parseInt(elements[i].value);
}
document.tickets.totalCost.value = '£' + totalCost;
}
</script>
</head>
<body>
<form name="tickets" id="tickets">
<!--FIRST CLASS that takes the value entered and * by the ticket price for an adult. Price is £18 * Number of Tickets -->
<label for="noAdults"> Number of Adults</label>
<select name="noAdults" id="noAdults" class="adultTotal" onclick="Calc('adultTotal')">
<option value="0" >0</option>
<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>
</select>
<label for="pricing"> X £18</label><br><br>
<!--Not class as children under 2 are not charged-->
<label for="childUnder2"> Number of Children aged 2 or less </label>
<select name="childUnder2" id="childUnder2">
<option value="0" >0</option>
<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>
</select>https://stackoverflow.com/questions/ask?title=auto%20calculate%20values%20onclick#
<label for="pricing"> X £FREE</label><br><br>
<!--SECOND CLASS that takes the value entered and * by the ticket price for a child ages 3-10. Price is £10 * Number of Tickets -->
<label for="childBox1"> Number of Children aged 3-10</label>
<select name="childBox1" id="childBox1" class="childBox1" onclick="Calc('childBox1')">
<option value="0" >0</option>
<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>
</select>
<label for="pricing"> X £10</label><br><br>
<!--EDIT CLASS that takes the value entered and * by the ticket price for a child ages 11-16. Price is £13 * Number of Tickets -->
<label for="childBox2"> Number of Children aged 11-16</label>
<select name="childBox2" id="childBox2" class="childBox2" onclick="Calc('childBox2')">
<option value="0" >0</option>
<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>
</select>
<label for="pricing"> X £13</label><br><br>
<!--If checked, the priced is double from that of a single ticket. Total price is * 2. -->
<input type="checkbox" name="rtnJourney" id="rtnJourney" value="2" onclick="Calc('rtnJourney')">Return Journey - If unchecked, price is halved<br>
Total: <input type="text" id="totalCost" name="totalCost">
</form>
</body></html>
Now I understand why the above JS code doesn't work and I fetched this from one of the examples online which took every value from a CLASS and combined them but since I have different multiplication values for each entry I tried to modify it which didn't workout. I am not sure how to do what I need it to do to calculate the total. Also please note that it doesn't add the values yet, for now I just want to make it calculate the total from all the fields.
p.s I am really not familiar with JS and I really appreciate any help given.

<html>
<head>
<meta charset="utf-8">
<title>Calculator</title>
<script language="javascript">
var map = {
"noAdults": {
value: 0,
multiplier: 18
},
"childUnder2": {
value: 0,
multiplier: 0
},
"childBox1": {
value: 0,
multiplier: 10
},
"childBox2": {
value: 0,
multiplier: 13
}
}
var rtnJourney = false;
function displayTotal() {
var total = 0;
for (var key in map) {
total += map[key].value * map[key].multiplier;
}
total = rtnJourney ? total * 2 : total;
document.tickets.totalCost.value = '£' + total;
}
function getTotal(dom) {
map[dom.id].value = dom.value;
displayTotal();
}
function getChecked(dom) {
rtnJourney = dom.checked;
displayTotal();
}
</script>
</head>
<body>
<form name="tickets" id="tickets">
<!--FIRST CLASS that takes the value entered and * by the ticket price for an adult. Price is £18 * Number of Tickets -->
<label for="noAdults"> Number of Adults</label>
<select name="noAdults" id="noAdults" class="adultTotal" onchange="getTotal(this)">
<option value="0">0</option>
<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>
</select>
<label for="pricing"> X £18</label>
<br>
<br>
<!--Not class as children under 2 are not charged-->
<label for="childUnder2"> Number of Children aged 2 or less </label>
<select name="childUnder2" id="childUnder2" onchange="getTotal(this)">
<option value="0">0</option>
<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>
</select>https://stackoverflow.com/questions/ask?title=auto%20calculate%20values%20onclick#
<label for="pricing"> X £FREE</label>
<br>
<br>
<!--SECOND CLASS that takes the value entered and * by the ticket price for a child ages 3-10. Price is £10 * Number of Tickets -->
<label for="childBox1"> Number of Children aged 3-10</label>
<select name="childBox1" id="childBox1" class="childBox1" onchange="getTotal(this)">
<option value="0">0</option>
<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>
</select>
<label for="pricing"> X £10</label>
<br>
<br>
<!--EDIT CLASS that takes the value entered and * by the ticket price for a child ages 11-16. Price is £13 * Number of Tickets -->
<label for="childBox2"> Number of Children aged 11-16</label>
<select name="childBox2" id="childBox2" class="childBox2" onchange="getTotal(this)">
<option value="0">0</option>
<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>
</select>
<label for="pricing"> X £13</label>
<br>
<br>
<!--If checked, the priced is double from that of a single ticket. Total price is * 2. -->
<input type="checkbox" name="rtnJourney" id="rtnJourney" value="2" onchange="getChecked(this)">Return Journey - If unchecked, price is halved
<br> Total:
<input type="text" id="totalCost" name="totalCost">
</form>
</body>
</html>

hide dropdown option on change of another dropdown option

I have tried this, but not working fine. HTML:
<div>
<select id="color" name="color" onchange="myFunction()">
<option value=""> choose options </option>
<option value="1">AB</option>
<option value="2">ABC</option>
<option value="3">ABCD</option>
</select>
<select id="size" name="size" >
<option value=""> choose options </option>
<option value="3" class="27">Apple </option>
<option value="2" class="26">Orange</option>
<option value="2" class="26">Orange</option>
<option value="2" class="26">Orange</option>
<option value="3" class="28">Grapes</option>
</select>
</div>
SCRIPT:
function myFunction()
{
$variable=$("#size").html();
$("#size").html($variable);
var val=$("#color").find(":selected").val();
$("#size option[value!="+val+"]").remove();
}
in place of .remove() I tried .hide() which seems to be not working. Could anyone help me out with this?

You should show all options before hide.
function myFunction()
{
$variable=$("#size").html();
$("#size").html($variable);
var val=$("#color").find(":selected").val();
$("#size option").show();
$("#size option[value!="+val+"]").hide();
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div>
<select id="color" name="color" onchange="myFunction()">
<option value=""> choose options </option>
<option value="1">AB</option>
<option value="2">ABC</option>
<option value="3">ABCD</option>
</select>
<select id="size" name="size" >
<option value=""> choose options </option>
<option value="3" class="27">Apple </option>
<option value="2" class="26">Orange</option>
<option value="2" class="26">Orange</option>
<option value="2" class="26">Orange</option>
<option value="3" class="28">Grapes</option>
</select>
</div>

You can make a mix of JS and CSS.
So we "reset" the size select, by removing all the disabled and also the selected.
Something like this:
$(document).ready(function () {
var colors = $('#color'),
size = $('#size');
colors.change(function () {
var val = $(this).find(":selected").val();
size.find('option').removeAttr('disabled');
size.find('option:selected').removeAttr('selected');
size.find("option[value!=" + val + "]").attr('disabled', 'disabled');
})
})
option:disabled {
display: none;
}
option:first-child {
display: block;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>
<select id="color" name="color">
<option value="">choose options</option>
<option value="1">AB</option>
<option value="2">ABC</option>
<option value="3">ABCD</option>
</select>
<select id="size" name="size">
<option value="">choose options</option>
<option value="3" class="27">Apple</option>
<option value="2" class="26">Orange</option>
<option value="2" class="26">Orange</option>
<option value="2" class="26">Orange</option>
<option value="3" class="28">Grapes</option>
</select>
</div>
Edit 1:
Using data-group instead of class or value
$(document).ready(function () {
var colors = $('#color'),
size = $('#size');
colors.change(function () {
var val = $(this).find(":selected").attr('data-group');
size.find('option').removeAttr('disabled');
size.find('option:selected').removeAttr('selected');
size.find("option[data-group!=" + val + "]").attr('disabled', 'disabled');
})
})
option:disabled {
display: none;
}
option:first-child {
display: block;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>
<select id="color" name="color">
<option value="">choose options</option>
<option value="1" data-group="1">AB</option>
<option value="2" data-group="2">ABC</option>
<option value="3" data-group="3">ABCD</option>
</select>
<select id="size" name="size">
<option value="">choose options</option>
<option value="3" class="27" data-group="3">Apple</option>
<option value="2" class="26" data-group="2">Orange</option>
<option value="2" class="26" data-group="2">Orange</option>
<option value="2" class="26" data-group="2">Orange</option>
<option value="3" class="28" data-group="3">Grapes</option>
</select>
</div>

Filter the dropdown using jquery

I have a drop down which lists several countries and I want to display only a few countries depending on some conditions.
jquery is as below:
function form_onLoad() {
var countries = "";
if(document.forms[0].countries_new) {
countries = document.forms[0].countries_new.value;
}
}
Dropdown :
<select name="country" size="1">
<option value=""></option>
<option value="1" >Afghanistan</option>
<option value="2" >Albania</option>
<option value="3" >Algeria</option>
<option value="4" >Andorra</option>
<option value="5" >Angola</option>
<option value="6" >Antigua & Deps</option>
<option value="7" >Argentina</option>
<option value="8" >Armenia</option>
<option value="9" >Australia</option>
<option value="10" >Austria</option>
<option value="11" >Azerbaijan</option>
<option value="12" >Bahamas</option>
</select>
Inside the jquery, I want to replace the existing dropdown(above) which has all countries with the countries variable which has only a few options.

You can use JQuery library to achieve it
$('select[name="country"]').find('option').each(function(){
if($(this).text()=='Armenia' || $(this).attr('value')=='12'){
$(this).remove(); //It will remove Armenia and Bahamas
}
});

Prevent selecting same value in three different dropdowns

I have three dropdowns. I want that when the user selects any item from dropdown 1, then that item should be disabled in dropdown 2 and 3. Also, if an item is selected in dropdown 2, then both selected items must be disabled from dropdown 3.
Here is the code I am using:
<!DOCTYPE html>
<html>
<head>
<script>
function updateSelect(changedSelect, selectId) {
var otherSelect = document.getElementById(selectId);
for (var i = 0; i < otherSelect.options.length; ++i) {
otherSelect.options[i].disabled = false;
}
if (changedSelect.selectedIndex == 0) {
return;
}
otherSelect.options[changedSelect.selectedIndex].disabled = true;
}
</script>
</head>
<body>
<select id="select_1" onchange="updateSelect(this,'select_2'),updateSelect(this,'select_3');" name="indication_subject[]">
<option value="" selected="selected">a </option>
<option value="1"> Accounting</option>
<option value="2"> Afrikaans</option>
<option value="3"> Applied Information and Communication Technology</option>
<option value="4"> Arabic</option>
<option value="5"> Art and Design</option>
<option value="6"> Biology</option>
<option value="7"> Business Studies</option>
</select>
<select id="select_2" name="indication_subject[]" onchange="updateSelect(this,'select_1','select_3');" >
<option value="" selected="selected">a </option>
<option value="1"> Accounting</option>
<option value="2"> Afrikaans</option>
<option value="3"> Applied Information and Communication Technology</option>
<option value="4"> Arabic</option>
<option value="5"> Art and Design</option>
<option value="6"> Biology</option>
<option value="7"> Business Studies</option>
</select>
<select id="select_3" name="indication_subject[]" onchange="updateSelect(this,'select_1','select_2');" >
<option value="" selected="selected">a </option>
<option value="1"> Accounting</option>
<option value="2"> Afrikaans</option>
<option value="3"> Applied Information and Communication Technology</option>
<option value="4"> Arabic</option>
<option value="5"> Art and Design</option>
<option value="6"> Biology</option>
<option value="7"> Business Studies</option>
</select>
</body>
</html>
Below is the JSFiddle link which works for two dropdowns, not three. How can I add a third dropdown for this?
http://jsfiddle.net/x4E5Q/1/

Try This:
HTML
<select id="select1" name="indication_subject[]">
<option value="" selected="selected">a </option>
<option value="1"> Accounting</option>
<option value="2"> Afrikaans</option>
<option value="3"> Applied Information and Communication Technology</option>
<option value="4"> Arabic</option>
<option value="5"> Art and Design</option>
<option value="6"> Biology</option>
<option value="7"> Business Studies</option>
</select>
<select id="select2" name="indication_subject[]">
<option value="" selected="selected">a </option>
<option value="1"> Accounting</option>
<option value="2"> Afrikaans</option>
<option value="3"> Applied Information and Communication Technology</option>
<option value="4"> Arabic</option>
<option value="5"> Art and Design</option>
<option value="6"> Biology</option>
<option value="7"> Business Studies</option>
</select>
<select id="select3" name="indication_subject[]">
<option value="" selected="selected">a </option>
<option value="1"> Accounting</option>
<option value="2"> Afrikaans</option>
<option value="3"> Applied Information and Communication Technology</option>
<option value="4"> Arabic</option>
<option value="5"> Art and Design</option>
<option value="6"> Biology</option>
<option value="7"> Business Studies</option>
</select>
JS
$(document).ready(function(){
$("select").change(function() {
$("select").not(this).find("option[value="+ $(this).val() + "]").attr('disabled', true);
});
});
Demo

See below code
$(document).ready(function() {
$("select").on('hover', function () {
$previousValue = $(this).val();
}).change(function() {
$("select").not(this).find("option[value='"+ $(this).val() + "']").attr('disabled', true);
$("select").not(this).find("option[value='"+ $previousValue + "']").attr('disabled', false);
});
});
$("#confirm-form").submit(function(e) {
e.preventDefault();
$("select").find("option").removeAttr('disabled');
document.getElementById('confirm-form').submit();
});

$(document).ready(function(){
$("select").on('focus', function () {
$("select").find("option[value='"+ $(this).val() + "']").attr('disabled', false);
}).change(function() {
$("select").not(this).find("option[value='"+ $(this).val() + "']").attr('disabled', true);
});
});