make a select dependent with js - javascript

I would like to do a select option dependent of another select, i saw there's a way using array with fixed values, but my array is reloaded every time we add a new form field on the form. I would like something like when i select op1, then it just show op1 options on second select.
<select id="id1" name="optionshere">
<option relone="op1">opt one</option>
<option relone="op2">opt two</option>
</select>
<select id="id2" name="resulthere">
<option relone="op1">ans 1 op1</option>
<option relone="op1">ans 2 op2</option>
<option relone="op2">ans 1 op2</option>
</select>
Any idea?
thanks all

Here's a method without jQuery:
When you select an option in the first selectbox, it will hide everything that doesn't match its relone.
var id1 = document.getElementById("id1");
var id2 = document.getElementById("id2");
id1.addEventListener("change", change);
function change() {
for (var i = 0; i < id2.options.length; i++)
id2.options[i].style.display = id2.options[i].getAttribute("relone") == id1.options[id1.selectedIndex].getAttribute("relone") ? "block" : "none";
id2.value = "";
}
change();
<select id="id1" name="optionshere">
<option relone="op1">opt one</option>
<option relone="op2">opt two</option>
</select>
<select id="id2" name="resulthere">
<option relone="op1">ans 1 op1</option>
<option relone="op1">ans 2 op1</option>
<option relone="op2">ans 1 op2</option>
</select>

If Jquery is an option you may go with something like this:
<script type='text/javascript'>
$(function() {
$('#id1').change(function() {
var x = $(this).val();
$('option[relone!=x]').each(function() {
$(this).hide();
});
$('option[relone=x]').each(function() {
$(this).show();
});
});
});
</script>
Then to expand:
There really are many ways in which you can solve this predicament, depending on how variable your pool of answers is going to be.
If you're only interested in using vanilla javascript then let's start with the basics. You're going to want to look into the "onchange" event for your html, so as such:
<select onchange="myFunction()">
Coming right out of the w3schools website, on the Html onchange event attribute:
The onchange attribute fires the moment when the value of the element
is changed.
This will allow you to make a decision based on this element's value. Then inside your js may branch out from here:
You may use Ajax and pass to it that value as a get variable to obtain those options from a separate file.
You may get all options from the second div through a combination of .getElementbyId("id2") and .getElementsByTagName("option") then check for their individual "relone" attribute inside an each loop, and hide those that don't match, and show those that do.
Really, it's all up to what you want to do from there, but I personally would just go for the Jquery approach

Related

When registering both onchange and onclick on a select, the click event is triggered twice

Goal: Have a select whose option have nested structure when user clicks on the select, but when user selects an option the option should be displayed "normally" (ie with no leading spaces).
Attempted solution using JS and Jquery: My JS is far from sophisticated so I apologize in advance :)
I attempted to use .on("change") and .on("click") to change the selected option value (by calling .trim() since I achieve the "nested" structure with ). I'm also storing the original value of the selected option because I want to revert the select menu to its original structure in case the user selects another option.
The problem: The function registered for .on("click") is called twice, thus the select value immediately resets itself to its original value.
I suspect there is a much, much easier solution using CSS. I will be happy to accept an answer that will suggest such solution.
JSFiddle: https://jsfiddle.net/dv6kky43/9/
<form>
<select id="select">
<option value=""></option>
<option value="a"> a</option>
<option value="b"> b</option>
</select>
</form>
<textarea id="output"/>
var orig;
var output = $("#output");
output.val("");
function onDeviceSelection(event){
output.val(output.val() + "\nonDeviceSelection");
var select = event.target;
orig = select.selectedOptions[0].text;
select.selectedOptions[0].text = select.selectedOptions[0].text.trim()
}
function resetDeviceSelectionText(event) {
output.val(output.val() + "\nresetDeviceSelectionText");
var select = event.target;
if (orig !== undefined){
select.selectedOptions[0].text = orig;
}
}
$("#select").on("change", onDeviceSelection);
$("#select").on("click", resetDeviceSelectionText);
If you are already using jQuery, why not utilize data function to store the original value. This way you will also be able to specify different nest levels.
(function($){
$(document).on('change', 'select', function(event) {
$(this).find('option').each(function(index, element){
var $option = $(element);
// Storing original value in html5 friendly custom attribute.
if(!$option.data('originalValue')) {
$option.data('originalValue', $option.text());
}
if($option.is(':selected')) {
$option.html($option.data('originalValue').trim());
} else {
$option.html($option.data('originalValue'));
}
})
});
})(jQuery);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form>
<select id="select">
<option value=""></option>
<option value="a"> a</option>
<option value="b"> b</option>
</select>
</form>
Once caveat I see is, the selected option will appear trimmed on the list as well, if dropdown is opened after a previous selection has been made:
Will it still work for you?
Instead of keeping the state of the selected element i would simply go over all options and add the space if that option is not selected:
function onDeviceSelection(event){
// Update textarea
output.val(output.val() + "\nonDeviceSelection");
// Higlight the selected
const {options, selectedIndex} = event.target;
for(let i = 0; i < options.length; i++)
options[i].innerHTML = (i === selectedIndex ? "":" ") + options[i].text.trim();
}
$("#select").on("change", onDeviceSelection);
Note that you need to use innerHTML to set the whitespace...

Remove and add values from dropdown using javascript/jQuery

I am trying to achieve the following thing in my code but it is getting complicated.
I have 'n' dropdowns with or without duplicate values in it.
for simplicity lets assume following scenario:
dropdown1:
<select>
<option>100</option>
<option>200</option>
<option>102</option>
</select>
dropdown 2:
<select>
<option>100</option>
<option>200</option>
<option>201</option>
</select>
dropdown3 :
<select>
<option>100</option>
<option>300</option>
<option>301</option>
</select>
case1:
if user select value 100 from dropdown 1 then 100 should be removed from all the dropdowns.and when user change dropdown 1 value from 100 to 200 then 100 should be added back to all the dropdowns and 200 should be removed from all the dropdowns.
removing seems easy but adding back values is little difficult.
how can I maintain a list or some other data structure to remember which value to add and where incase of multiple value change? is there any advance jquery feature or generic javacript logic i can use ?
If it is sufficient to just disable the option instead of actually removing it, the following could work for you. You might want to adapt the handling of the selects when initially loading the site.
$('select option[value="' + $('select').eq(0).val() + '"]').not(':eq(0)').prop('disabled', true);
$('select').on('change', function() {
var val = $(this).val();
$('select option').prop('disabled', false);
$('select option[value="' + val + '"]').not($(this)).prop('disabled', true);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select>
<option value='100'>100</option>
<option value='200'>200</option>
<option value='102'>102</option>
</select>
<select>
<option value='100'>100</option>
<option value='200'>200</option>
<option value='201'>201</option>
</select>
<select>
<option value='100'>100</option>
<option value='300'>300</option>
<option value='301'>301</option>
</select>
It would be better to set display to none instead. Hence, you will avoid the complications of adding or removing in the appropriate order.
So, you can easily return them visible.
$( "option" ).each(function( index ) {
$(this).css("display", "");
});
$("#drop").change(function () {
var selected_value=$(this).val();
var dropdown=$(select);
for(i=0;i<dropdown.length;i++){
$("dropdown[i] option[value=selected_value]").remove();
}
});
Set id of first dropdown="drop"
Here select the value and define it S a variable loop through dropdown with in page remove option when value=selected_value

jquery not getting value from select statement on change

This is really odd, but I am probably missing something simple. I have a simple select statement where a user can choose a value.
onChange calls a function getDrop2() which currently I am trying to get it to alert me which option is chosen.
my html is:
<select onChange= "getDrop2()" id = "drop1" >
<option value="0">All</option>
<option value="1">Alphabetical</option>
<option value="2">Brewery</option>
<option value="3">Style</option>
</select>
My Javascript is:
function getDrop2(){
var choice = $("#drop1").val()
alert(choice);
}
The output of the alert statement is just blank.
In jQuery, you're better off doing something like:
<select id = "drop1" >
<option value="0">All</option>
<option value="1">Alphabetical</option>
<option value="2">Brewery</option>
<option value="3">Style</option>
</select>
With the following JavaScript:
$(function(){
$('#drop1').change(function() {
var choice = $(this).val();
alert(choice);
}
});
The idea is that jQuery is now attaching the change function automatically to the select with the id of "drop1" By using this pattern, you've decoupled the HTML from the JavaScript that's doing the business logic.
Although what others have selected is a better approach. My answer is just to tell you why your code is not working
Try this
var choice = $('#drop1 option:selected').val()
Instead of
var choice = $("#drop1").val()

Set HTML attribute value using java Script

I have html drop down list,which has country list. Now I want to set current country as a default value of list. I found the JavaScript code for get country using Geolocation.
My code:
function getCountry(var name) {
if(name==geoip_country_name()) {
return "selected";
}
}
Then I need to set the selected attribute of the option list.
I tried this:
<option value="Sri Lanka" selected="getCountry('sri Lanka')">Sri Lanka</option>
But this is not correct.
Basically I want to set selected attribute value using JavaScript function
How do I do that?
Use the window.onload event, and just set the dropdown's value. Keep in mind that your hard coded country names may differ from the geo service.
<script>
window.onload = function(){
document.getElementById("country").value = geoip_country_name();
}
</script>
<select id="country" name="country">
<option value="Sri Lanka">Sri Lanka</option>
<option value="UK">UK</option>
<option value="USA">USA</option>
<select>
Basically you can do it like this:
<html>
<body>
<select id="country">
<option id="germany" value="Germany">DE</option>
<option id="uk" value="UK">UK</option>
<option id="usa" value="USA">USA</option>
</select>
<script>
var selectedCountry = 'uk'; //getCountry
var index = document.getElementById(selectedCountry).index;
document.getElementById("country").selectedIndex=index;
</script>
Start the script after your select is rendered.
Note, that this example might not be best practice. I'm also not sure if it works in all browsers (Opera works). You might use an appropriate framework like JQuery, Mootools, ...
The selected attribute is not automatically evaluated as JS code. Assuming you have stored the desired country name in the variable country, could try this instead:
var country = "Sri Lanka";
var select = document.getElementById('myselect'); //Change to the ID of your select element
for (var i = 0; i < select.options.length; i++){
if(select.options[i].value == country)
select.selectedIndex = i;
}
If you are using JQuery following line should solve your problem:
$('select').val(geoip_country_name());
If geoip_country_name returns names in lower case, While initializing the select list, value for each option be in lower case.

Javascript to hide select box elements not working in IE

Hey, not sure if I'm going about this the right way. I have two different select boxed. What needs to happen is when a certain item in box 1 is selected, certain items in box 2 are hidden. What I have works fine in FF but not in IE....thoughts?
<div>
<label class="form_label">Apparel</label>
<select id="Choices" size="1" style="clear: right;" onchange"changeThis();">
<option value="select">Pick Your Product</option>
<option value="1">choice 1</option>
<option value="2">choice 2/option>
<option value="3">choice 3</option>
</select>
</div>
<div>
<label class="form_label">Size</label>
<select id="Sizes" size="1" style="clear: right;">
<option value="select">Choose Your Size</option>
<option value="SC">Small Child</option>
<option value="IC">Intermediate Child</option>
<option value="MC">Medium Child</option>
</select>
</div>
...
function changeThing(choice)
{
var item = document.getElementById("Choices");
var size = document.getElementById("Sizes");
var selitem = item.options[item.selectedIndex].value;
if(selitem == '2546')
{
for(i=0; i<2; i++)
{
size[i].style.display = 'none';
//alert(size[i]);
}
}
Try using this instead:
http://www.w3schools.com/CSS/pr_class_visibility.asp
It would come out as:
size[i].style.visibility='hidden';
EDIT
Oh, welcome to StackOverflow!
I had the same problem some days ago. IE does not allow the using of visible:hidden or display:none for option element.
You can solve this problem storing the options of select1 in a variable. This variable will have all possible values, so when the value of select1 was changed you can remove all values of select2 and then get the options you need from variable to put into select2.
To summarize:
Store all possible values in a variable
When select1 was changed remove all options of select2
Filter the options(get these values from varible of step1) you need and put into select2
You cannot display:none remove will completely remove it, if you want the user not to choose it use disabled. you could do something like this
function changeThing()
{
var item = document.getElementById("Choices");
var size = document.getElementById("Sizes");
var selitem = item.options[item.selectedIndex].value;
if(selitem == '3')
{
for(i=1; i<2; i++) // filter logic here
{
size[i].disabled = true; //false - to reset
//alert(size[i]);
}
}
size.selectedIndex = 0; // reset the selection so a disabled item may not be selected. }
It depends on how you are firing off the event that calls the changeThing() function. Not sure about IE9, but IE8 and on back has issues with the onChange event. It basically avoids it in IE. You'll have to use onClick instead.
If you are using jQuery to fire the event, the onchange event should work correctly in all browser (even IE). Not sure how other Javascript libraries do it.
You need to remove this options completely to make it work in IE.
size.remove(i);
So you need to store your options in array and load it back when needed.

Categories

Resources