Develop Reference

Adding and removing from count when checkbox is checked/unchecked with javascript/jquery?

I'm relatively new to JS, so I'm getting a little stuck with this:
Let's say I have 40 checkboxes, but a user can select no more than 10.
I have the checkboxes set out, labelled checkbox1, checkbox2 etc right up to 40. The user cannot select more than 10. How would I go about doing this?
The way I thought of doing it would be like this, but I'm unsure whether or not this would work, due to obviously having 40 fields and then what if they uncheck one?
function checkValidation() {
if (document.getElementById('checkbox1').isChecked()) {
document.getElementById('validation').value() + 1;
}
}
So every time it's checked, it would add 1 to the textbox validation and then I could do an if statement to say if validation.value() > 8 then alert out to say they can't check anymore.
I think that's not the best way, as if they uncheck the box, my function won't take this in consideration?
Hopefully this makes sense, if anything needs clarification please let me know and I can explain further.

Try the following way:
$('#myBtn').click(function(){
var countCheckd = $('input[type=checkbox]:checked').length;
if(countCheckd >= 3){
console.log('You have 3 or more checked: ' +countCheckd);
}
else{
console.log('You have less than 3 checked: ' +countCheckd);
}
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="checkbox" />1
<input type="checkbox" />2
<input type="checkbox" />3
<input type="checkbox" />4
<input type="checkbox" />5
<br><br>
<input type="button" id="myBtn" value="Check"/>

You can add a class on all your considered checkboxe, called for example chk.
Then you declare your count function :
function countCheck(){
return $(".chk:checked").length;
}
Finally you add an event on your checkboxes click :
$(document).on("click",".chk",function(){
var numberChecked = countCheck();
//update your input
$("#validation").val(numberChecked );
});

Just make an event of checkbox click and check for the count of each click, in below example if the click is exceeded then 5 it gives an alert message and won't be allowed to click more checkboxes.
$(function(){
for(var i=0;i<=30;i++){
$(".test").append("checkbox "+i+"<input type='checkbox' name='chk[]' class='check' id='check_"+i+"'><br />");
}
})
$(document).on("click",".check",function(){
var checked = $(".check:checked").length
if(checked > 5){
alert("Maximum 5");
return false;
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<div class='test'>
</div>

You can try something like this:
$('input[type=checkbox]').on('change', function (e) {
if ($('input[type=checkbox]:checked').length > 10) {
$(this).prop('checked', false);
alert("Only 10 selection is allowed");
}
});

This code is unchecking previous checkbox if checked input's length more than 10:
$('input[type="checkbox"]').on('click', function(){
var max=0;
var t=$(this);
$('input[type="checkbox"]:checked').each(function(){
if($(this).data('oops')>max){
max=$(this).data('oops');
}
});
t.data('oops', (max+1));
if($('input[type="checkbox"]:checked').length>10){
$('input[type="checkbox"]:checked').each(function(){
if($(this).data('oops')==max){
$(this).prop('checked', false);
}
});
}
});
Without adding global variable.
See

This works:
// these are global variables
var checkBoxChecks = 0;
var maxChecks = 10;
$('input[type="checkbox"]').on('click', function()
{
// if the currently clicked checkbox is now checked
if(this.checked)
{
if(checkBoxChecks < maxChecks) checkBoxChecks++;
else
{
this.checked = false;
alert("You have reached the maximum amount of " + maxChecks + " checks.");
}
}
else checkBoxChecks--;
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />

Return a string based on checkbox checked

I have a table with 2 checkboxes:
<table>
<tr>
<td>
<label for="A">
<input type="checkbox" name="A" id="A" value="true" />
A
</label>
<label for="B">
<input type="checkbox" name="B" id="B" value="true" />
B
</label>
</td>
</tr>
</table>
and I want to be able to identify which box is checked (by id), and be able to store a string as a variable, depending on the box. Here is my javascript:
var getCheck = function() {
if (document.getElementById('A').checked) {
return "A";
}
else if (document.getElementById('B').checked){
return "B";
}
else if ((document.getElementById('A').checked) && (document.getElementById('B').checked)) {
return "Both"
}
console.log(getCheck); // for debugging
};
So if I check 'A', I want getCheck to = 'A' as a string. Curious as to how to fix my Javascript to get it to work.

Here's an example of how you would do it with jQuery, it's just easier to do with it and since there's a jQuery tag...
Basically, you add a handler for elements that are checkboxes. Then you select only checked checkboxes with :checked and then you just access each element with the jQuery each function.
$(function(){
$('input[type=checkbox]').on('change', function(){
var checked = [];
$('input[type=checkbox]:checked').each(function(index, checkbox){
checked.push($(checkbox).attr('id'));
});
$('#result').text(JSON.stringify(checked, '/t'));
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<table>
<tr>
<td>
<label for="A">
<input type="checkbox" name="A" id="A" value="true" />
A
</label>
<label for="B">
<input type="checkbox" name="B" id="B" value="true" />
B
</label>
</td>
</tr>
</table>
<pre id="result"></pre>

You need to check both first, since otherwise the function will return "A" and never reach the code that would return both. It is also possible to eliminate all the if-else complexity when returning from each if.
A helper function and some variables can reduce repetition and code length.
var isChecked = function(id){
var e = document.getElementById(id);
return (e && e.checked);
}
var getCheck = function() {
var A = isChecked("A");
var B = isChecked("B");
if (A && B) return "Both";
if (A) return "A";
if (B) return "B";
return "None";
}
For testing, you could add
window.onclick = function(){ console.log(getCheck()); }
demo via jsfiddle

fiddle example
The answer others provided is quite good for. And I want to make some addition:
If you want to get the value whenever user check the box, you can add a eventListen to the parent table as a delegation for the checkbox. Just as I show in the fiddle example
<table id="mytable">
<tr>
<td>
<label for="A">
<input type="checkbox" name="A" id="A" value="true" />
A
</label>
<label for="B">
<input type="checkbox" name="B" id="B" value="true" />
B
</label>
</td>
</tr>
</table>

check all checkboxes javascript

I'm trying to have all checkboxes checked (true) when the user clicks on "All" button. I tried this, firstly just to see if "Anglais" could be checked clicking on "All" :
<input type="checkbox" name="anglais" id="anglais" value="Anglais" /> Anglais
<input type="checkbox" name="allemand" id="allemand" value="Allemand" /> Allemand
<input type="checkbox" name="espagnol" id="espagnol" value="Espagnol" /> Espagnol
<input type="checkbox" name="francais" id="francais" value="Francais" /> Francais
<input type="checkbox" onclick="checkedAll()" name="all" id="all" value="Tous" /> Tous
My Javascript :
function checkedAll () {
var checked = false;
var all = document.getElementById('all');
if (checked == false) {
checked = true
}
else {
checked = false
}
var ang = document.getElementById('anglais').checked
if (ang == true) {
ang.checked = true;
}
But the button(s) are not checked when I click on All. I think I don't understand exactly how to use the .checked method..
Maybe, some of my code has not logic, because it was from this example :
https://www.hscripts.com/scripts/JavaScript/select-all-checkbox.php

Couple modifications:
Pass in the all checkbox to the checkedAll method (this allows you to reference it without having to re-find it).
Used document.getElementsByTagName to find the other checkboxes, but you could just as easily use document.getElementById for each one (anglais, allemand, etc.)
Set every other checkbox's checked status to the all.checked value. No need for a true/false comparison.
function checkedAll(allCheckbox){
var allCheckboxes = document.getElementsByTagName('input');
for (var i = 0; i < allCheckboxes.length; i++){
var curCheckbox = allCheckboxes[i];
if (curCheckbox.id != 'all'){
curCheckbox.checked = allCheckbox.checked;
}
}
}
<input type="checkbox" name="anglais" id="anglais" value="Anglais" /> Anglais
<input type="checkbox" name="allemand" id="allemand" value="Allemand" /> Allemand
<input type="checkbox" name="espagnol" id="espagnol" value="Espagnol" /> Espagnol
<input type="checkbox" name="francais" id="francais" value="Francais" /> Francais
<input type="checkbox" onclick="checkedAll(this)" name="all" id="all" value="Tous" /> Tous
The more explicit way would be:
function checkedAll(){
var isAllChecked = document.getElementById('all').checked;
// Set the other checkboxes .checked property based on the
// .checked status of the `all` checkbox
document.getElementById('anglais').checked = isAllChecked;
document.getElementById('allemand').checked = isAllChecked;
document.getElementById('espagnol').checked = isAllChecked;
document.getElementById('francais').checked = isAllChecked;
}
<input type="checkbox" name="anglais" id="anglais" value="Anglais" /> Anglais
<input type="checkbox" name="allemand" id="allemand" value="Allemand" /> Allemand
<input type="checkbox" name="espagnol" id="espagnol" value="Espagnol" /> Espagnol
<input type="checkbox" name="francais" id="francais" value="Francais" /> Francais
<input type="checkbox" onclick="checkedAll()" name="all" id="all" value="Tous" /> Tous

jquery checkboxes, how to get all selected checkboxes and add them to array?

Hi I have the following page:
<input type="checkbox" name="fruit1" id="1" class="box">Banana<br /><br />
<input type="checkbox" name="fruit2" id="2" class="box">Cherry<br /><br />
<input type="checkbox" name="fruit3" id="3" class="box">Strawberry<br /><br />
<input type="checkbox" name="fruit4" id="4" class="box">Orange<br /><br />
<input type="checkbox" name="fruit5" id="5" class="box">Peach<br /><br />
<input type="button" id="groupdelete" value="clickme"><br />
$(document).ready(function(){
$('#groupdelete').on('click', function(){
var names = [];
$('input:checked').each(function() {
names.push($('input:checked').attr("name") + $('input:checked').attr('id'));
});
console.log(names);
})
})
What I am trying to do is the following:
To add the checked checkboxes in the array. And after that, I would like to be able to pass the value in php variable.
When I excecute the code now, I am getting result like this:
["fruit22", "fruit22", "fruit22"]
Any help will be deeply appreciated.
Regards, Zoreli

You need to use this rather than 'input:checked' inside the .each() function to refer to the current element in the set being examined. If you re-use the selector you're getting the set again, then only ever getting the attributes from the first element in the set.
$('input:checked').each(function() {
names.push($(this).attr("name") + this.id);
});

Change your html to
<input type="checkbox" name="fruits[]" id="1" class="box">Banana<br /><br />
<input type="checkbox" name="fruits[]" id="2" class="box">Cherry<br /><br />
<input type="checkbox" name="fruits[]" id="3" class="box">Strawberry<br /><br />
<input type="checkbox" name="fruits[]" id="4" class="box">Orange<br /><br />
<input type="checkbox" name="fruits[]" id="5" class="box">Peach<br /><br />
<input type="button" id="groupdelete" value="clickme"><br />
And now, look to jQuery/Javascript
$(document).ready(function(){
$('#groupdelete').click(function() {
var marked = new Array();
var k = 0;
$('input:checked').each(function(index,value) {
marked[k] = value;
k++;
});
alert(marked[0].id);
});
});
alert is just giving you the demo by accessing the direct access on the array's index.

jquery: how to check if all radio buttons in a div are selected

my html looks like this
<div id="div1">
<input type="radio" name="r1" value="v1" />
<input type="radio" name="r1" value="v2" />
<input type="radio" name="r1" value="v3" />
<input type="radio" name="r2" value="v1" />
<input type="radio" name="r2" value="v2" />
<input type="radio" name="r2" value="v3" />
<input type="radio" name="r3" value="v1" />
<input type="radio" name="r3" value="v2" />
<input type="radio" name="r3" value="v3" />
</div>
radio buttons are dynamically generated on my html so in that div i don't know how many radio buttons i have.
i want to make sure that the user will select a value for each one of them before he submits the form, how can i check that all radio buttons inside my div has a value checked?
Thank you

$(":radio").change(function() {
var names = {};
$(':radio').each(function() {
names[$(this).attr('name')] = true;
});
var count = 0;
$.each(names, function() {
count++;
});
if ($(':radio:checked').length === count) {
alert("all answered");
}
}).change();
Demo: http://jsfiddle.net/yFaAj/15/

Restructure your HTML slightly - wrap each radio group in (say) a div. Then you can just do something like this to validate the form when the user submits it:
if ($('div:not(:has(:radio:checked))').length) {
alert("At least one group is blank");
}
Of course this can be tweaked in various ways to suit your HTML. The idea was from Find all radio groups which haven't been selected

Solution here http://jsfiddle.net/QxdnZ/1/
var checked = $("#div1 :radio:checked");
var groups = [];
$("#div1 :radio").each(function() {
if (groups.indexOf(this.name) < 0) {
groups.push(this.name);
}
});
if (groups.length == checked.length) {
alert('all are checked!');
}
else {
var total = groups.length - checked.length;
var a = total>1?' groups are ':' group is ';
alert(total + a + 'not selected');
}

Validate the form when the user submits it, using this validation code.
var blank = false;
$("input:radio").each(function() {
var val = $('input:radio[name=' + this.name + ']:checked').val();
if (val === undefined) {
blank = true;
return false;
}
});
alert(blank ? "At least one group is blank" : "All groups are checked");
First we get the names of all the radio button groups, then check that each one has a value. (Actually we're doing multiple checks, but that doesn't really matter.)

Looking for something along these lines? http://jsfiddle.net/gXsZp/3/
<div id="div1">
Q1
<input type="radio" name="r1" value="v1" />
<input type="radio" name="r1" value="v2" />
<input type="radio" name="r1" value="v3" />
<br/>Q2
<input type="radio" name="r2" value="v1" />
<input type="radio" name="r2" value="v2" />
<input type="radio" name="r2" value="v3" />
<br/>Q3
<input type="radio" name="r3" value="v1" />
<input type="radio" name="r3" value="v2" />
<input type="radio" name="r3" value="v3" />
</div>
<br/>
<input id="btn" type="submit" text="submit"/>
$('#btn').click(function(){
if ( $('#div1 input:radio:checked').size() == 3 )
return true;
return false;
});

Try this one:
$('input:radio', $('#div1')).each(function() {
if(name && name == $(this).attr('name'))
return true; // Skip when checking the same element name.
name = $(this).attr('name');
if(! $('input:radio[name="' + name + '"]:checked').length) {
alert('Oops, you missed some input there.. [' + name + ']');
return false;
}
});
It will loop through every radio button to check for checked radio & will break as soon it found non-checked radio group (first error found). But if you prefer to get all the errors (not only the first error found), just remove return false.

Try this:
function check(){
var allCheck = true;
if($("#div1 :radio:checked").length==0){
allCheck=false;
}
$("#div1 :radio").each(function(){
for(var i=0;i<$("#div1 :radio:checked").length;i++)
if($(this).attr("name")===$($("#div1 :radio:checked")[i]).attr("name"))
break;
else if(i==$("#div1 :radio:checked").length-1)
allCheck = false;
});
return allCheck;
}

This will work:
if($("#div1").children("input:radio:checked").size() == 3)
{
alert('three inputs were checked');
}