English is not my first language. I'm sorry..  

I'm always trying to avoid using external modules like jQuery, Angular and so on.

In jQuery,

```
$('.desc').addClass('active');

```

This can be alternate like

```
function addClasses(className, class)
{
    cl = doc.getElementsByClassName(className);
    len=cl.length;
    for(var i=0;len<i;i++)
    {
        cl[i].classList.add(class);
    }
}

addClasses('desc', 'active');

```

It's more long but it behave same also We can save 85kb of jQuery Script file.  

I think this approach is not bad and believe It could reduce more resource and increase performance. and It can apply directly if you share some codes in communities without installing external modules... add them to document... I hate those things really.  

But I often use Codepen.io and even here stackoverflow communities, they all use jQuery or some external modules although it can be alternate a single line code.  
Am i wrong? is jQuery and the other external modules does not effect on performances and resources thing? because actually, it's more easy to use and as a result, it makes more short script.