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Select another dropdown value based on the previous dropdown selection

I am new to html javascript and trying to learn it. I am having an issue that when I select a value of a dropdown it will select another dropdown value when certain criteria matches.
If they Select the option 4 (takeout) from service_type dropdown, the counter dropdown will automatically selected the option 2 driveway. else user are free to select any value on both dropdown. Only if they select Takeout, it will make driveway selected and also make the table service option inactive.
if they select 1,2 or 3 from the Service type dropdown then option 1 will be enabled.
I need a javascript and no jquery. Please help me
<div class="form-group col-md-12">
<select name="service_type" id="service_type" class="form-control form-control-line" required>
<option value="" selected="selected" >Select Service</option>
<option value="1">Dining</option>
<option value="2">Beverages</option>
<option value="3">Liquor</option>
<option value="4">Takeout</option>
</select>
</div>
<div class="form-group col-md-12">
<select name="counter" id="counter" class="form-control form-control-line" required>
<option value="" selected="selected" >Select Counter</option>
<option value="1">Table Service</option>
<option value="2">Driveway</option>
</select>
</div>

You can use javascript like this:
function Checker(el){
const select = document.getElementById('counter');
removeOptions(select);
if(el.value == '4'){
var option1 = document.createElement("option");
option1.text = "Driveway";
option1.value = "2";
select.add(option1);
}else{
var option2 = document.createElement("option");
option2.text = "Table Service";
option2.value = "1";
select.add(option2);
var option1 = document.createElement("option");
option1.text = "Driveway";
option1.value = "2";
select.add(option1);
}
}
function removeOptions(selectElement) {
var i, L = selectElement.options.length - 1;
for (i = L; i >= 0; i--) {
selectElement.remove(i);
}
}
<div class="form-group col-md-12">
<select name="service_type" id="service_type" class="form-control form-control-line" onChange="Checker(this)" required>
<option value="" selected="selected" >Select Service</option>
<option value="1">Dining</option>
<option value="2">Beverages</option>
<option value="3">Liquor</option>
<option value="4">Takeout</option>
</select>
</div>
<div class="form-group col-md-12">
<select name="counter" id="counter" class="form-control form-control-line" required>
<option value="" selected="selected" >Select Service Fist</option>
</select>
</div>
Create two function one for create option base to first choise and second for remove option everytime function is called.

const firstSelect = document.querySelector('#serviceType');
const secondSelect = document.querySelector('#counter');
firstSelect.addEventListener('change', (event) => {
if (event.target.value === '4') {
secondSelect.value = '2';
secondSelect.disabled = true;
} else if (typeof event.target.value === 'string' && event.target.value.length > 0) {
secondSelect.disabled = false;
secondSelect.value = '1';
} else {
secondSelect.disabled = false;
secondSelect.value = '';
}
});
<div class="form-group col-md-12">
<select name="service_type" id="serviceType" class="form-control form-control-line" required>
<option value="" selected="selected" >Select Service</option>
<option value="1">Dining</option>
<option value="2">Beverages</option>
<option value="3">Liquor</option>
<option value="4">Takeout</option>
</select>
</div>
<div class="form-group col-md-12">
<select name="counter" id="counter" class="form-control form-control-line" required>
<option value="" selected="selected" >Select Counter</option>
<option value="1">Table Service</option>
<option value="2">Driveway</option>
</select>
</div>
How does it work?
You need to select your Select controls from DOM and then listen to change event on first select, then you can get value from it and depending on your choice change value of Select #2. In order to disable ability to choose another option in second dropdown, you can disable it.

Second dropdown value is not changing if I doesn't change my first dropdown

I am trying to show a table of reviews by taking the value of two dropdowns. When I was having one dropdown(positive, negative etc) that works fine but when I introduce another dropdown(food, drinks etc) it is not working.
It only works when I change the first dropdown and second dropdown but if I kept the first dropdown unchanged then it's not working
I tried by adding onchange method to the second dropdown. I just started with Javascript so not much idea about what to try.
function printResult(form) {
var output = {
{
output | safe
}
};
var sel = form.list;
var sel2 = form.list2;
var selectedVal = sel.options[sel.selectedIndex].value;
var selectedVal2 = sel2.options[sel.selectedIndex].value;
//document.getElementById("showResult").innerText = "Your number is: " + selectedVal;
//console.log(output);
document.getElementById("showResult").innerText = "Your number is: " + selectedVal2;
}
<form action="dropdown" onSubmit="return printResult(this);">
<label for="sentiment">Sentiment</label>
<div class="styled-select blue semi-square">
<select name="list">
<option value="all">All</option>
<option value="positive">Positive</option>
<option value="negative">Negative</option>
<option value="neutral">Neutral</option>
</select>
</div>
<div>
<select name="list2" onChange="printResult()">
<option value="menu">Menu Range</option>
<option value="food">Food</option>
<option value="drinks">Drinks</option>
<option value="desserts">Desserts</option>
</select>
</div>
<input type="submit" value="Filter">
<span id="showResult"></span>
</form>

You need to pass the form on the change too and return false to not submit the form:
function printResult(form) {
var sel = form.list;
var sel2 = form.list2;
var selectedVal = sel.value;
var selectedVal2 = sel2.value;
document.getElementById("showResult").innerText = "Your number is: " + selectedVal2;
return false;
}
<form action="dropdown" onSubmit="return printResult(this);">
<label for="sentiment">Sentiment</label>
<div class="styled-select blue semi-square">
<select name="list">
<option value="all">All</option>
<option value="positive">Positive</option>
<option value="negative">Negative</option>
<option value="neutral">Neutral</option>
</select>
</div>
<div>
<select name="list2" onChange="printResult(this.form)">
<option value="menu">Menu Range</option>
<option value="food">Food</option>
<option value="drinks">Drinks</option>
<option value="desserts">Desserts</option>
</select>
</div>
<input type="submit" value="Filter">
<span id="showResult"></span>
</form>
Perhaps you wanted this instead
window.addEventListener("load", function() {
document.getElementById("form1").addEventListener("submit", function(e) {
e.preventDefault(); // stop submission
var sel = this.list;
var sel2 = this.list2;
var selectedVal = sel.value;
var selectedVal2 = sel2.value;
document.getElementById("showResult").innerText = (selectedVal && selectedVal2) ? selectedVal + ":" + selectedVal2 : "Please select both";
});
});
<form action="dropdown" id="form1">
<label for="sentiment">Sentiment</label>
<div class="styled-select blue semi-square">
<select name="list">
<option value="">All</option>
<option value="positive">Positive</option>
<option value="negative">Negative</option>
<option value="neutral">Neutral</option>
</select>
</div>
<div>
<select name="list2">
<option value="">Menu Range</option>
<option value="food">Food</option>
<option value="drinks">Drinks</option>
<option value="desserts">Desserts</option>
</select>
</div>
<input type="submit" value="Filter">
<span id="showResult"></span>
</form>

How to get the OPTION's TEXT value

In this case, only primary dropdown will change, other dropdowns' values will change automatically according to it (so users wont be changing them) I'm trying to get the Option's TEXT value using PHP with $_POST. But i can only get it when i manually changed the other dropdown .
I have tried to use the trigger() method, but it fails to get the option text value. Any idea why the code fails to work. Thank you.
function setDropDown() {
var index_name =
document.getElementsByName('ForceSelection')[0].selectedIndex;
var others = document.querySelectorAll('.secondary');
for (var i = 0; i < others.length; i++) {
others[i].selectedIndex = index_name;
}
}
<!-- try to get the option text value and pass it to input field-->
<!-- Then in the php code use $_POST[] to retrieve the input value-->
function setTextField(ddl) {
document.getElementById('make_text').value = ddl.options[ddl.selectedIndex].text;
}
$("select").trigger("change");
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form action="" method="post">
<div><b>Primary dropdown:</b>
<select name="ForceSelection" id="ForceSelection" onChange="javascript:return setDropDown();">
<option value="" selected>Select</option>
<option value="treatmentid1">treatmentname1</option>
<option value="treatmentid2">treatmentname2</option>
</select>
</div>
<div>
<b>Other dropdown 1</b>:
<select class='secondary' id="Qualifications" name="Qualifications" onChange="setTextField(this)">
<option value="select">select</option>
<option value="treatmentid1">treatmentname1</option>
<option value="treatmentid2">treatmentname2</option>
</select></div>
<input id="make_text" type="hidden" name="make_text" value="" />
<div> <b>Other dropdown 2</b>:
<select class='secondary' id="Qualifications2" name="Qualifications2">
<option value="select">select</option>
<option value="treatmentid1">treatmentname1</option>
<option value="treatmentid2">treatmentname2</option>
</select>
</form>
PHP Code
$value =$_POST['make_text'];

Html element <select> onchange doesn't fire for programmatic changes, you need to fire it yourself with
$(".secondary").trigger("change");
or by Id
$("#Qualifications").trigger("change");
The problem is that your hidden <input> never had the value. if you remove the hidden it on your code you can check it.
So when you POSTED the values the value on make_text was empty string. So if you fire the trigger after the for loop then it will work.
function setDropDown() {
var index_name = document.getElementsByName('ForceSelection')[0].selectedIndex;
var others = document.querySelectorAll('.secondary');
for (var i = 0; i < others.length; i++) {
others[i].selectedIndex = index_name;
}
$("#Qualifications").trigger("change");
}
function setTextField(ddl) {
document.getElementById('make_text').value = ddl.value;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form action="" method="post">
<div><b>Primary dropdown:</b>
<select name="ForceSelection" id="ForceSelection" onChange="javascript:return setDropDown();">
<option value="" selected>Select</option>
<option value="treatmentid1">treatmentname1</option>
<option value="treatmentid2">treatmentname2</option>
</select>
</div>
<div>
<b>Other dropdown 1</b>:
<select class='secondary' id="Qualifications" name="Qualifications" onChange="setTextField(this)">
<option value="select">select</option>
<option value="treatmentid1">treatmentname1</option>
<option value="treatmentid2">treatmentname2</option>
</select></div>
<input id="make_text" name="make_text" value="" />
<div> <b>Other dropdown 2</b>:
<select class='secondary' id="Qualifications2" name="Qualifications2">
<option value="select">select</option>
<option value="treatmentid1">treatmentname1</option>
<option value="treatmentid2">treatmentname2</option>
</select>
</form>

I have to say that I don't see any need to use a hidden input text to POST data to PHP because you can just post the value of the <select> and retrieve it in PHP like this $force = $_POST["ForceSelection"];.
Otherwise, if you want to continue what you started, you can change your setDropDown() function to this :
function setDropDown() {
#Get the selected value of the ForceSelection select :
var index_name = $('#ForceSelection').val();
#Change the value of the other secondary select :
$(".secondary").each(function( index ) {
$(this).val(index_name).change();//This will change the value and trigger the change event.
});
}

HTML/JS/Django Hiding incompatible options from two picklists

I'm running a filter for my object on a django-run website.
I have two select fields, with dropdowns based on related models to my model that i'd like to sort.
The problem is that some options are incompatible with each another and i'd like to hide the options of the second picklist based on what the user has selected on the first one.
I feel like i am going to use some JS but i've never used it before.
1st picklist: tasks <option value = task_id>
2nd picklist: crafts <option value = craft_id>
I have prepared a dictionnary that holds all the compatible values of any option selected on the first picklist, if that can help !
useful_dictionnary = {
first_task_id = [list_of_compatible_craft_ids]
...
last_task_id = [list_of_compatible_craft_ids]
}
How can i get JS to look at the task_id selected on the first picklist, and hide the options from the second picklist that are not in this list ?
Would be great! Thanks !
Here is my picklists code, if that helps
<div class="form-group col-sm-4 col-md-3">
<label for="id_tasks">Tasks:</label>
<select class="form-control" id="id_tasks" name="task">
<option value="">---------</option>
<option value="1" selected="selected">Tie-job: Front-tie Marker</option>
<option value="2">Tie-job: Scrapmachine support trackman</option>
<option value="3">Tie-job: Plate Thrower</option>
<option value="4">Tie-job: New-tie Marker</option>
</select>
</div>
<div class="form-group col-sm-4 col-md-3">
<label for="id_craft">Craft:</label>
<select class="form-control" id="id_craft" name="craft">
<option value="" selected="selected">---------</option>
<option value="1">Senior Engineer</option>
<option value="2">Roadmaster</option>
<option value="3">Foreman</option>
<option value="4">Assistant Foreman</option>
<option value="5">Electrical Welder EA</option>
<option value="6">Oxygen Welder OA</option>
<option value="7">Railway Machine Operator (RMO)</option>
<option value="8">Truck Driver (Type A, B or C)</option>
</select>
</div>

This snippet should do the trick. Change compatibleIds to map the options for the second select based on the first one.
$(document).ready(function(){
$("#id_craft option:not([value=0])").hide();
});
$("#id_tasks").change(function(){
$("#id_craft").val("0");
$("#id_craft option:not([value=0])").hide();
var compIds = { 1: [ 1,2,3,4,5], 3 : [ 4,2,3,8,7], 4 : [ 7,9,1,5], 2 :[5,3,1,8]};
for(var i = 0; i < compIds[$("#id_tasks").val()].length; i++){
$("#id_craft option[value=" + compIds[$("#id_tasks").val()][i] + "]").show();
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="form-group col-sm-4 col-md-3">
<label for="id_tasks">Tasks:</label>
<select class="form-control" id="id_tasks" name="task">
<option value="0" selected="selected">---------</option>
<option value="1">Tie-job: Front-tie Marker</option>
<option value="2">Tie-job: Scrapmachine support trackman</option>
<option value="3">Tie-job: Plate Thrower</option>
<option value="4">Tie-job: New-tie Marker</option>
</select>
</div>
<div class="form-group col-sm-4 col-md-3">
<label for="id_craft">Craft:</label>
<select class="form-control" id="id_craft" name="craft">
<option value="0" selected="selected">---------</option>
<option value="1">Senior Engineer</option>
<option value="2">Roadmaster</option>
<option value="3">Foreman</option>
<option value="4">Assistant Foreman</option>
<option value="5">Electrical Welder EA</option>
<option value="6">Oxygen Welder OA</option>
<option value="7">Railway Machine Operator (RMO)</option>
<option value="8">Truck Driver (Type A, B or C)</option>
</select>
</div>
Small add-on as the original question was about a django dictionary object:
To use a django list or dictionnary in the javascript, it is pretty straightforward as the {{ django_variable }} works fine inside the script tags.
So the final JS for this django template page is:
$(document).ready(function(){
$("#id_craft option:not([value=0])").hide();
});
$("#id_tasks").change(function(){
$("#id_craft").val("0");
$("#id_craft option:not([value=0])").hide();
var compatibleIds = {{ my_python_dictionary }};
for(var i = 0; i < compatibleIds[$("#id_tasks").val()].length; i++){
$("#id_craft option[value=" + compatibleIds[$("#id_tasks").val()][i] + "]").show();
}
});

Multiple show / hide jquery

My code below is showing the proper city/state div's when the matching country is selected from the drop down, but it's not hiding the previous one if the user decides to select another state. Do I have to create an if/else each for each div i want to hide?
<script type="text/javascript">
$(document).ready(function() {
...
//city & state display
$("#ctry").change(function() {
$(".state").hide();
var stateSelect = $("#state_" + $(this).val());
if (stateSelect.length === 0)
$("#state_label").hide();
else {
$("#state_label").show();
stateSelect.show();
}
});
});
</script>
html code:
<label>Country/Locale:</label>
<select id="ctry" name="country">
<option value="">-- Select</option>
<option value="US">United States</option>
<option value="CA">Canada</option>
<option value="GB">United Kingdom</option>
<option value="AU">Australia</option>
</select><br />
<!-- US -->
<div id="state_US" style="display:none">
<label id="state_label" style="display:none">State:</label>
<span class="rstate">
<select name="u_state">
<option value="">-- State US</option>
<option value="AL">Alabama</option>
</select>
</span>
Zip or City:<input style="margin-left:43px;" type="text" name="locus" id="locus" size="30" />
</div>
<!-- CA -->
<div id="state_CA" style="display:none">
<label id="state_label" style="display:none">Province:</label>
<span class="rstate">
<select name="c_state">
<option value="">-- Prov CA</option>
<option value="ON">Windsor</option>
</select>
</span>
Postal or Place:<input style="margin-left:43px;" type="text" name="locca" id="locca" size="30" />
</div>
<!-- GB -->
<div id="state_GB" style="display:none">
<label id="state_label" style="display:none">City or Region:</label>
<span class="rstate">
<select name="k_state">
<option value="">-- Place</option>
<option value="AU">UK!</option>
</select>
</span>
</div>
<!-- AU -->
<div id="state_AU" style="display:none">
<label id="state_label" style="display:none">City or Region:</label>
<span class="rstate">
<select name="a_state">
<option value="">-- Place</option>
<option value="AU">UK!</option>
</select>
</span>
</div>

Remove the state_label ids..
Add the unused class state to the state_CA, state_US etc. elements..
So each state group should be
<div id="state_US" class="state" style="display:none">
<label style="display:none">State:</label>
<span class="rstate">
<select name="u_state">
<option value="">-- State US</option>
<option value="AL">Alabama</option>
</select>
</span>
Zip or City:<input style="margin-left:43px;" type="text" name="locus" id="locus" size="30" />
</div>
And change your script to be
<script type="text/javascript">
$(document).ready(function() {
...
//city & state display
$("#ctry").change(function() {
$(".state").hide();
var stateSelect = $("#state_" + $(this).val());
stateSelect.show();
});
});
</script>
Demo at http://jsfiddle.net/gaby/PYx2v/

You cannot have multiple elements with the same ID. Your label state_Label is not unique. You should change this, otherwise some browsers will not show your label.
You hide all elements having the css-class "state". But there is no element having this class. I guess that you need to add class="state" to all of your state_*-divs.

Something like this logic might work for you:
var previous;
$(document).ready(function() {
$("#ctry").change(function() {
$(".state").hide();
var stateSelect = $("#state_" + $(this).val());
if (stateSelect.length === 0) {
$("#state_label").hide();
} else {
if (previous) {
previous.hide(function() {
$("#state_label").show();
stateSelect.show();
previous = stateSelect;
});
} else {
$("#state_label").show();
stateSelect.show();
previous = stateSelect;
}
}
});
});
Though it would be easier if they all had the same CSS class, with which you could easily hide them and then show the one that was selected.