How to Lazy-Load external scripts for better page speed?

Article autor
September 9, 2025
How to Lazy-Load external scripts for better page speed?
Elixir Newsletter
Join Elixir newsletter

Subscribe to receive Elixir news to your inbox every two weeks.

Oops! Something went wrong while submitting the form.
Elixir Newsletter
Expand your skills

Download free e-books, watch expert tech talks, and explore open-source projects. Everything you need to grow as a developer - completely free.

Table of contents

Nowadays, with an ever-growing number of web services, we tend to overload Web apps with external resources. As a result, it decreases page load speed and affects SEO score. There is a pretty easy solution for that.

Let's assume that you'd like to use the chatbot on your website. Fetching all resources might take in this case, for example, 2 seconds (which is not that unusual - trust me).

Even if your website is fully optimized to load fast, users will still have to wait 2 more seconds for full interaction.

In this case, if you don't need a chatbot to appear immediately, you can lazy-load the script:

setTimeout(function () {
  var d = document,
    s = d.createElement("script");
  s.src = "path-to-js-script";
  d.body.appendChild(s);
}, 5000);

That's it. After 5 seconds, a chatbot will be fetched and attached to the body of your website.

It's important to use a time interval that is long enough to run after the page is fully loaded. In this example, I used 5s interval, but you should use the one that match to your specific case.

Work with a team that keeps learning and building better software every day.

Related posts

Dive deeper into this topic with these related posts

No items found.

You might also like

Discover more content from this category

How to check if a set contains exact values with Jest in JS?

TLDR: With jest-extended package you can write: expect([...set]).toIncludeSameMembers([value1, value2]);. If you are looking to a native, but longer solution scroll down a bit.

Implicit try in Elixir

In the world of Elixir programming, there are numerous features and syntactic constructs that contribute to the language's elegance and expressiveness. One such hidden gem is the concept of "implicit try".

How to process Phoenix conn after render before it is sent as a response

There are a bunch of operations you may want to perform before the rendered response in conn is sent to the client, such as minification. In this post I'll show you how to do it easily.