jQuery counting elements by class – what is the best way to implement this?

jQuery counting elements by class – what is the best way to implement this?

What I’m trying to do is to count all of the elements in the current page with the same class and then I’m going to use it to be added onto a name for an input form. Basically I’m allowing users to click on a and then by doing so add another one for more of the same type of items. But I can’t think of a way to count all of these simply with jQuery/JavaScript.
I was going to then name the item as something like name=”whatever(total+1)”, if anyone has a simple way to do this I’d be extremely grateful as JavaScript isn’t exactly my native tongue.

Solutions/Answers:

Solution 1:

Should just be something like:

// Gets the number of elements with class yourClass
var numItems = $('.yourclass').length


As a side-note, it is often beneficial to check the length property before chaining a lot of functions calls on a jQuery object, to ensure that we actually have some work to perform. See below:

var $items = $('.myclass');
// Ensure we have at least one element in $items before setting up animations
// and other resource intensive tasks.
if($items.length)
{
  $items.animate(/* */)
    // It might also be appropriate to check that we have 2 or more
    // elements returned by the filter-call before animating this subset of 
    // items.
    .filter(':odd')
      .animate(/* */)
      .end()
    .promise()
    .then(function () { 
       $items.addClass('all-done');
    });
}

Solution 2:

Getting a count of the number of elements that refer to the same class is as simple as this

<html>
    <head>
        <script src="http://code.jquery.com/jquery-1.4.2.min.js"></script>
        <script type="text/javascript">

            $(document).ready(function() {
                alert( $(".red").length );
            });

        </script>
    </head>
    <body>

        <p class="red">Test</p>
        <p class="red">Test</p>
        <p class="red anotherclass">Test</p>
        <p class="red">Test</p>
        <p class="red">Test</p>
        <p class="red anotherclass">Test</p>
    </body>
</html>

Solution 3:

var count = $('.' + myclassname).length;

Solution 4:

for counting:

$('.yourClass').length;

should work fine.

storing in a variable is as easy as:

var count = $('.yourClass').length;

Solution 5:

HTML:

<div>
    <img src='' class='class' />
    <img src='' class='class' />
    <img src='' class='class' />
</div>

JavaScript:

var numItems = $('.class').length; 

alert(numItems);

Fiddle demo for inside only div

Solution 6:

try

document.getElementsByClassName('myclass').length
let num = document.getElementsByClassName('myclass').length;
console.log('Total "myclass" elements: '+num);
.myclass { color: red }
<span class="myclass" >1</span>
<span>2</span>
<span class="myclass">3</span>
<span class="myclass">4</span>