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Hide an option in a multiple select, when a specific option has been selected from another select

I have seen questions similar to this but mine is different.
so I have these first 2 dropdown menu (data are selected from my database) and another dropdown which is attributed with multiple,
now my code works on the first 2 dropdowns but when it comes to the multiple dropdown it's not working.
here are my dropdown menu;
<select class="custom-select" name="option_one">
<option>test1</option>
<option>test2</option>
<select class="custom-select" name="option_two">
<option>test1</option>
<option>test2</option>
<select id="multiple" class="custom-select" name="option_three[]" multiple="multiple">
<option>test1</option>
<option>test2</option>
Here is my javascript
$(document).ready(function() {
function intializeSelect() {
$('.custom-select').each(function(box) {
var value = $('.custom-select')[box].value;
if (value) {
$('.custom-select').not(this).find('option[value="' + value + '"]').hide();
}
});
};
intializeSelect();
$('.custom-select').on('change', function(event) {
$('.custom-select').find('option').show();
});
});

With a single on change attached to all select , you could check value and hide depending on innerHtml or value ( in your case no value , so checking by text) ,
What I've done is first showing all option , then check value if not undefined ,
if thre were a value hide other options input , that has same text value ,
See below working snippet :
$(document).ready(function() {
$('.custom-select').on('change', function(event) {
let value = $(this).val();
// show all options of all select
$('.custom-select').find("option").show();
// reset values after change of other select
$('.custom-select').not(this).val("");
if (value.length > 0) {
$('.custom-select')
.not(this)
.find("option")
.filter(function() {
return $(this).html() == value;
}).hide();
};
});
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<select class="custom-select" name="option_one">
<option></option>
<option>test1</option>
<option>test2</option>
</select>
<select class="custom-select" name="option_two">
<option></option>
<option>test1</option>
<option>test2</option>
</select>
<select id="multiple" class="custom-select" name="option_three[]" multiple="multiple">
<option></option>
<option>test1</option>
<option>test2</option>
</select>

I have two select boxes. I want to enable second select box only if i click a particular option in first select box [duplicate]

I have two dynamic dropdowns but both dropdown's value and options are same. What I want that if user select 'apple' from first dropdown then the second dropdown's apple option will be disabled (using javascript). In short user can not select same value from both.
//first drop down
<select name="fruit1">
<option value="1">Apple</option>
<option value="2">Mango</option>
</select>
//second dropdown
<select name="fruit2">
<option value="1">Apple</option>
<option value="2">Mango</option>
</select>
I have tried with jQuery:
function witness()
{
var op=document.getElementById("witness1").value;
$('option[value='+op+']').prop('disabled', true);
}
But with this both dropdown's value are disabled and if I select mango then apple will not enabled it remains disabled. I know I did not pass id so both dropdown value are disabled but where should i pass ?
If user select apple then in second dropdown apple will be disabled, I want to do this using Javascript or jQuery.

Fiddle: https://jsfiddle.net/3pfo1d1f/
To get the functionality you're after, you need to hook into the change event on the first dropdown, in order to disable the matching element in the second drop-down.
I also initialised the first element in the second dropdown as disabled ( as this chosen by default in the first dropdown)
Used jquery as you are:
HTML:
<!-- first dropdown -->
<select id="fruit1">
<option value="1">Apple</option>
<option value="2">Mango</option>
</select>
<br /> <br />
<!-- second dropdown -->
<select id="fruit2">
<option value="1" disabled>Apple</option>
<option value="2">Mango</option>
</select>
JQuery:
$('#fruit1').on( "change", function() {
var op = $( this ).val();
$('#fruit2 option').prop('disabled', false);
$('#fruit2 option[value='+op+']').prop('disabled', true);
});
This should still work, no matter how many options you have in both the dropdowns

Try this out:
HTML:
<select id='fruit1' onchange="witness();">
<option selected></option>
<option value="1">Apple</option>
<option value="2">Mango</option>
</select>
<select id='fruit2'>
<option selected></option>
<option value="1">Apple</option>
<option value="2">Mango</option>
</select>
JQuery:
function witness(){
$("#fruit2 option").each(function(){
if($("#fruit1 option:selected").val() == $(this).val())
$(this).attr("disabled", "disabled");
else
$(this).removeAttr("disabled");
});
}
You can see a working exemple here:
https://jsfiddle.net/mqjxL4n0/

<select name="firstselect" id="firstselect">
<option value="apple">Apple</option>
<option value="orange">Orange</option>
</select>
<select name="secondselect" id="secondselect">
<option value="apple">Apple</option>
<option value="orange">Orange</option>
</select>
<script>
$(document).ready(function(){
$('#firstselect').change(function(){
var firstselected = $(this).val();
if(firstselected ){
$('#secondselect option').each(function(){
$(this).prop('disabled', false);
if($(this).val()==firstselected )
$(this).prop('disabled', true);
});
}
else {
$('#secondselect option').each(function(){
$(this).prop('disabled', false);
});
}
});
});
</script>

pass element ID as a parameter to jquery

I have a select box on a web form that, depending on what is selected, will show a hidden div.
<script>
$(document).ready(function () {
$("#Select1").change(function () {
$(this).find("option:selected").each(function(){
if($(this).attr("Value")=="2"){
$("#hiddentable11").show();
}
else if($(this).attr("Value")=="3"){
$("#hiddentable11").show();
}
else{
$("#hiddentable11").hide();
}
});
}).change();
});
</script>
The form will have 35 to 40 of these Select box/hidden div combinations. The option values in the select boxes will all be the same every time (0,1,2,3,4). If the user chooses option 2 or 3 for Select1, hiddentable11 appears. If they choose option 2 or 3 for Select2, hiddentable 12 appears I don't want to copy/paste this code 40 times and in the code change Select1/hiddentable11 to Select2/hiddentable12, Select3/hiddentable13 etc. How do I change this code so that I can reuse it for all of the select/div combinations?

Give all the select boxes a class, e.g. class="select". Then you can usethis.id` to get the ID of the target element, and concatenate it to the DIV id.
$(".select").change(function() {
var num = this.id.slice(6); // get N from id="SelectN"
$("#hiddentable1" + num).toggle($(this).val() == "2" || $(this).val() == "3"));
});

Then just make a .Select class, and use this, pass in the corresponding hidden table as a user defined unique data attribute (I'll use data-hidden as an example). Then you can create the proper selector for each item by doing "#"+$(this).attr("data-hidden"):
$(".Select").change(function () {
$(this).find("option:selected").each(function(){
if($(this).attr("Value")=="2") {
$("#"+$(this).attr("data-hidden")).show();
}
else if($(this).attr("Value")=="3") {
$("#"+$(this).attr("data-hidden")).show();
}
else {
$("#"+$(this).attr("data-hidden")).hide();
}
});
}).change();

Try this. With this you don't need to depend on ID's. You may multiple select boxes to your code and table combo and never have to change your js code.
<select id="select1">
<option val="0">0</option>
<option val="1">1</option>
<option val="2">2</option>
<option val="3">3</option>
<option val="4">4</option>
</select>
<div id="hiddentable11">
Hidden Contents of Select1
</div>
<select id="select2">
<option val="0">0</option>
<option val="1">1</option>
<option val="2">2</option>
<option val="3">3</option>
<option val="4">4</option>
</select>
<div id="hiddentable12">
Hidden Contents of Select2
</div>
<select id="select3">
<option val="0">0</option>
<option val="1">1</option>
<option val="2">2</option>
<option val="3">3</option>
<option val="4">4</option>
</select>
<div id="hiddentable13">
Hidden Contents of Select3
</div>
$("select").change(function () {
var index = $('select').index($(this));
index++;
var $this = $(this).find("option:selected").val();
$("#hiddentable1" + index).css("display", $this === "2" || $this === "3" ? "inline-block" : "none");
});
http://jsfiddle.net/njzatgku/1/

Validating multiple select box

Select box 1
<select name="slt_drop1" id = "slt_drop1">
<option value ="0">----------</option>
...........
</select>
Select box 2
<select name="slt_drop2" id = "slt_drop2">
<option value ="0">----------</option>
...........
</select>
Select box 3
<select name="slt_drop3" id = "slt_drop3">
<option value ="0">----------</option>
...........
</select>
Select box 4
<select name="slt_drop4" id = "slt_drop4">
<option value ="0">----------</option>
...........
</select>
In a HTML form I've used 4 select buttons, if the user selects the value as "0" i.e (Default value) in any of the select button it should show message near to the select button , "please select the correct value" for that particular for example if the value of slt_drop3 is "0" it should alert near slt_drop3 select option . The message should be displayed for individual button and not common alert .

maybe this is what you want ? Demo
$("select").change(function()
{
if($(this).val() == "0")
$(this).after(' <small> please select the correct value</Small>');
else
if($(this).next().prop("tagName").toLowerCase() == "small")
$(this).next().remove();
});
$("select").trigger("change");

Do you use jQuery in your project? I think you can listen when you change the value of select and validate it:
$(function() {
$('select').on('change', validate);
function validate(e) {
var select = $(e.currentTarget);
var id = select.attr('id');
var val = select.val();
if (val === '0') {
showMessage(id);
} else {
hideMessage(id);
}
}
function showMessage(id) {
$('.message[data-select-id="' + id + '"]').show();
}
function hideMessage(id) {
$('.message[data-select-id="' + id + '"]').hide();
}
});
Add blocks for messages near each select tag and show it if necessary
<select name="slt_drop1" id = "slt_drop1">
<option value ="0">----------</option>
...........
</select>
<div class='message' data-select-id='slt_drop1'>please select the correct value</div>

Add a common class to each SELECT element.
Use jQuery to select that elements which match that class.
Bind a change event to the selector and apply the logic to check for "0" value
$(document).ready(function() {
$('select.is-valid').change(function() {
var $el = $(this);
if($el.val() == 0) {
$el.after('<div>Select a different value</div>');
}
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select name="test[]" class="is-valid">
<option value="0">---</option>
<option value="1">1</option>
</select>
<select name="test[]" class="is-valid">
<option value="0">---</option>
<option value="1">1</option>
</select>
<select name="test[]" class="is-valid">
<option value="0">---</option>
<option value="1">1</option>
</select>
That's a basic example of what you're trying to achieve. Actual element/validation placement is up to you. I would recommend making a "Submit" button to check the validation but I assume you know how to do that.

Disable Drop Down Options Once Chosen In Other Dropdown

I have 12 drop downs input areas, 1 for each of the months of the year. Each drop down has the choice of the same 24 options.
I need to make it so that, for example, if in the January drop down box you chose option #4, that option #4 cannot be selected in any of the other drop down menus. It would still be in the drop down, but would just be disabled.
This would have an ajax trigger to check the value against the other drop downs and dynamically change the other drop down menus.
Is there a loop I can do to check and disable these values dynamically without having to make a lot of if statements?

You can use jQuery to find the option element in all other dropdowns (in my example, designated by a certain class...and can easily be changed to another selector - I thought the selector "select" was too broad), and then disable the actual option element by using .prop("disabled", true). But it's a little more tricky than this, as you need to keep track of the previous selected value to enable the dropdown again when a different value is chosen. Here's an example that will hopefully help:
http://jsfiddle.net/p5Arj/
$(document).ready(function () {
$(".test").each(function () {
var $self = $(this);
$self.data("previous_value", $self.val());
});
$(".test").on("change", function () {
var $self = $(this);
var prev_value = $self.data("previous_value");
var cur_value = $self.val();
$(".test").not($self).find("option").filter(function () {
return $(this).val() == prev_value;
}).prop("disabled", false);
if (cur_value != "") {
$(".test").not($self).find("option").filter(function () {
return $(this).val() == cur_value;
}).prop("disabled", true);
$self.data("previous_value", cur_value);
}
});
});
So this disables all other dropdowns' same options when you choose one, and makes sure that when you choose another, the previous one is enabled in all other dropdowns. For example, choose "3" in the first dropdown...look at the second dropdown - see that "3" is disabled...go back to the first dropdown and choose "1"...look at the second dropdown - see that "3" is enabled again but "1" is disabled. That's what the use of .data is for in my code.
Of course, you can replace the use of value with selectedIndex if you are 100% sure that all of the options will be the same for each select in question.

http://jsfiddle.net/Rk5e9/9/
Only about 10 lines, and no ajax!
<select class="unique-value">
<option value="-1" selected="selected">Default</option>
<option value="1">First</option>
<option value="2">Second</option>
<option value="3">Third</option>
</select>
<select class="unique-value">
<option value="-1" selected="selected">Default</option>
<option value="1">First</option>
<option value="2">Second</option>
<option value="3">Third</option>
</select>
<select class="unique-value">
<option value="-1" selected="selected">Default</option>
<option value="1">First</option>
<option value="2">Second</option>
<option value="3">Third</option>
</select>
Script:
$(document).ready(function(){
$('.unique-value').focus(function(){
var val = $(this).val();
$(this).attr('data-current-value', val);
});
$('.unique-value').change(function(){
var val = $(this).val();
if(val != -1)
$('.unique-value option[value=' + val + ']').attr('disabled', 'disabled');
var oldval = $(this).attr('data-current-value');
$('.unique-value option[value=' + oldval + ']').removeAttr('disabled');
});
});​

I think this would be the shortest solution:
<select class="select-value">
<option value="1">First</option>
<option value="2">Second</option>
<option value="3">Third</option>
</select>
<select class="select-value">
<option value="1">First</option>
<option value="2">Second</option>
<option value="3">Third</option>
</select>
<select class="select-value">
<option value="1">First</option>
<option value="2">Second</option>
<option value="3">Third</option>
</select>
and the jquery code:
$(document).on('change', '.select-attendee', function(){
$current=$(this);
$(".select-attendee").not($current).children("option[value='"+$current.val()+"']").attr('disabled', "disabled");
});

Assuming you had a dropdown for each month, and an option for each week.
<select class="month" id="october">
<option class="week" value="week1">Week One</option>
<option class="week" value="week2">Week Two</option>
</select>
Lets say you select a week, and you listen for the event.
$(".month").change(function(event) {
// Get the week just selected.
var selectedWeek = $(this).children(".week:selected").val();
// Enabled all weeks before disabling the selected week.
$("option.week").removeAttr("disabled");
// Disable all week options matching this selection.
$("option.week[value="+selectedWeek+"]").attr("disabled", "disabled");
});