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You Don’t Need jQuery

kdinnypaul profile image Dinny Paul ・3 min read

Ever wondered Why jQuery? is the most used Javascript library in the world and the most criticized one at the same time.

Well, jQuery has many advantages like it’s easy to use, it can manipulate web pages with few lines of code and its cross browser compatible, so why shouldn’t we use it?, the only problem is that it impacts web performance a lot.

Even a second delay can impact your website heavily, research shows that a one-second delay in site loading time will lead to a 7 percent loss in conversion, for Amazon, a one-second delay will result in a loss of $1.6 billion annually.

Why is jQuery Slow?

First and foremost in order to use jQuery you need to add an external javascript file like jquery.min.js which is of 30 kb size gzipped which will result in a 7 millisecond delay which doesn’t seem much but it adds up because you have to add it before your javascript code and most people add it into header so even that 7 millisecond delay is a lot, if you are on a mobile connection or slow internet then that delay increases drastically.

Now of course if you have added google’s jQuery url like https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js then its probably cached by the browser because a lot of websites use the same url and will load faster but its still an external call that too to a domain other than your own website which will add a small delay.

Apart from the delay caused by the external file, jQuery is much slower than pure javscript for example when appending a node to the DOM requires just a single call for Vanilla javscript, which interact directly with the DOM API, whereas jQuery runs a lot of operations for manipulating the DOM
which let me tell you matters a lot, nobody likes a website that is slow to use, I mean users could at one point accept the initial delay but they will not tolerate delay while they are interacting with the website.

Conclusion

So what should we do ?, Should we remove jQuery from every project?, well its not that easy to replace jQuery with pure javascript.

We could avoid using it though or replace it with some lightweight jQuery alternative like Cash OR Zepto.js or completely replace jQuery with pure javascript as they are supported by all modern browsers (IE9+), and are faster than jQuery.

if you want to replace jQuery with pure javascript below are some important code alternative to jQuery in pure javascript.

JavaScript GET Request

var request = new XMLHttpRequest();
request.open('GET', '/my/url', true);
request.onload = function() {
  if (request.status >= 200 && request.status < 400) {
    // Success!
    var resp = request.responseText;
  } else {
    // We reached our target server, but it returned an error
  }
};
request.onerror = function() {
  // There was a connection error of some sort
};
request.send();

JavaScript POST

var request = new XMLHttpRequest();
request.open('POST', '/my/url', true);
request.setRequestHeader('Content-Type',
'application/x-www-form-urlencoded; charset=UTF-8');
request.send(data);

JavaScript JSONP Request For Cross Domain Call

function onFetchComplete(data) {console.log(data);}

var script = document.createElement('script');

script.src = 'https://en.wikipedia.org/w/api.php?action=query&generator=random'+
'&grnnamespace=0&prop=extracts'+
'&exchars=500&format=json&callback=onFetchComplete';

document.body.appendChild(script);

JavaScript HIDE & SHOW

el.style.display = 'none';//HIDE
el.style.display = '';//SHOW

JavaScript Find

el.querySelectorAll(selector);

JavaScript After

el.insertAdjacentHTML('afterend', htmlString);

JavaScript Before

el.insertAdjacentHTML('beforebegin', htmlString);

JavaScript Append

parent.appendChild(el);

JavaScript Prepend

parent.insertBefore(el, parent.firstChild);

JavaScript Remove

el.parentNode.removeChild(el);

JavaScript Get Html

el.innerHTML

JavaScript Get Text

el.textContent

JavaScript Get Attributes

el.getAttribute('attributeName');

JavaScript Get Style

window.getComputedStyle(el, null).getPropertyValue("background-color");

JavaScript Get Outer Html

el.outerHTML

JavaScript Add Class

if (el.classList)
  el.classList.add(className);
else
  el.className += ' ' + className;

JavaScript Remove Class

if (el.classList)
  el.classList.remove(className);
else
  el.className = el.className.replace
(new RegExp('(^|\\b)' + className.split(' ').join('|') 
+ '(\\b|$)', 'gi'), ' ');

JavaScript Set Html

el.innerHTML = string;

JavaScript Set Text

el.textContent = string;

JavaScript Set Attributes

el.setAttribute('attributeName','attributeValue');

JavaScript Set Style

// Use a class if possible
el.style.borderWidth = '20px';

References

http://youmightnotneedjquery.com/
https://www.fastcompany.com/1825005/how-one-second-could-cost-amazon-16-billion-sales
https://medium.com/@trombino.marco/you-might-not-need-jquery-a-2018-performance-case-study-aa6531d0b0c3

Discussion

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prahladyeri profile image
Prahlad Yeri

in order to use jQuery you need to add an external javascript file like jquery.min.js which is of 30 kb size gzipped which will result in a 7 millisecond delay

That I think is the epitome of exaggeration! People don't seem to have any qualms about linking megabytes of bloat for "modern" things like vue, angular2, react, etc. for even announcement sites, and 30kb is suddenly a huge deal? If anything, this reflects nothing but people's prejudice towards jQuery.

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kdinnypaul profile image
Dinny Paul Author

It's not exaggeration have you read about render blocking javascript here's a link RenderBlockingJS

The problem is your js code can run only after your jquery is loaded and that is a huge disadvantage

In this article I'm comparing jQuery and pure javascript so that is disadvantage over pure javascript code which doesn't require an external js file besides the point the main reason why jQuery is bloated is to give support to old browsers which most ppl don't use anymore that's why I also suggested jQuery alternatives in this article

Now I didn't even mention about the external css required by Jquery in this article if you are going to display dialogs and other UI related stuff which slows your page even more

BTW I learned jQuery even before pure javascript and I wasted a lot of time in replacing jQuery I just want other developers to avoid it completely because time's have changed and with attention spans reducing more than ever even a second delay can have a huge impact on user experience

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jjlabajo profile image
JJ Labajo

I agree. And I feel the exaggeration, too, while reading.

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mervinsv profile image
Mervin

Oh! This is great.

Currently working on a project with almost everything are jquery. But wanted to remove jquery and start using pure javascript.

But the problem is we still need to import jquery because we are using a lot of jquery libraries like Bootstrap. Any suggestions about that?

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kdinnypaul profile image
Dinny Paul Author

You could try zepto.js but I don't know if it supports bootstrap completely, what you can do is try to remove jquery slowly or at least for DOM manipulation initially

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mervinsv profile image
Mervin

Okay. Thanks.

But I got this zurb.com/blog/why-we-dropped-zepto

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markel profile image
Markel F.

Super useful stuff, love it. JSON requests always made me go back to JQuery, cross-site policy is a little bit annoying 🙄.

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kdinnypaul profile image
Dinny Paul Author

Cross-site policy is annoying but you can use the below JSONP pure javscript code though

function onFetchComplete(data){console.log(data);}

var script = document.createElement('script');

script.src = 'https://en.wikipedia.org/w/api.php?action=query&generator=random&grnnamespace=0&prop=extracts&exchars=500&format=json&callback=onFetchComplete';

document.body.appendChild(script);