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 deal with timeout issue when debugging Phoenix app

There is a common scenario: You'd like to debug your Phoenix app with break!/4 or IEx.pry/0. Everything works fine, until... Phoenix server throws a timeout error statement.

How to get the struct type in Elixir

So you don’t know what’s the type of struct you’re passing somewhere? Maybe it can be one of few types and you have to distinguish them? Or any other reason… But it’s about checking the struct type. Just use one of the coolest Elixir features - pattern matching!

Skip file changes tracking in git

So, you’re changing this one file for local development purposes only. Maybe it’s config, maybe some source file, but one thing is certain - you don’t want those changes to be committed. And what’s worse, .gitignore doesn’t work.