How to use third-party JavaScript without impacting your web performance

How to use third-party JavaScript without impacting your web performance

Third-party JavaScript scripts, also known as tags, snippets, pixels, trackers or beacons, can be used to improve your web experience. They enable you to add capabilities, such as analytics, personalization, chatbots, or ads, but they can also come at a cost to performance. According to a recent Pingdom study of the world’s top 50 news websites, an average of 41 scripts were used on every page. In addition, sites that used third-party JavaScript loaded at an average 9.46 seconds, but when they were disabled loading times went down to just 2.69 seconds.

Even though they can be a drain on site resources, third-party scripts are no longer an optional part of modern web experiences. They are not only a great way for web development teams to keep up with consumer expectations, but they have also become essential for analysis, personalization, and other advanced functionality.

So, how do you leverage the power of third-party scripts without having a negative impact on the experience of your customers? There is no single solution, but there are several factors that will help the decision-making process when trying to achieve this balance.

Consider how you use third-party scripts

The first question you should be asking when implementing a third-party script is — does it serve a real purpose? If a third party gives you crucial information, provides helpful insights, or delivers functionality that will improve the overall experience, the benefits of adding it probably outweigh its potential risks. In cases where adding a third-party script provides only superficial functionality, it might not be worth it. It’s important to remember that every script can create drag on your web performance and even minor impact can end up adding up over time. Pick carefully, and evaluate which scripts truly make an impact for your users.

Set a web performance budget — and stick to it

To effectively understand the true cost to your website, use a performance budget during your development process to help you measure the performance impact. Performance budgets allow you to identify parameters for what is an acceptable load time and make decisions about what can be added without exceeding your limit. Tools like the performance budget calculator let you enter all the elements you want to include and calculate what you can add (or need to remove) in order to stay within budget. Sticking to your performance budget will help you to strike a healthy balance that allow you to deliver modern experiences that are also fast.

Avoid overcomplicating your experience

Aside from performance budgets, there are other techniques available to make sure your web app doesn’t get overloaded.

  1. Move all non-critical scripts out of the <head> and load them as late in the page as possible. If a script blocks the head from loading, the page can’t load.

  2. Use asynchronous loading and defer everything possible so that scripts execute after critical events, so they don’t have for them to fully load before starting to load themselves.

  3. Load as many third-party scripts as you can with the help of a tag manager. By combining third-party scripts together, your website will load faster.

In addition, you should conduct regular audits of your third-party scripts in order to keep things as simple as possible. As you think about implementing a script on your website, consider the following questions: What purpose does this third-party script serve? Is this the only way to provide this service? How will it impact web performance? Is this third party trustworthy and secure?

Secure your web experience

One of the biggest problems with relying on third parties is that traditional web application security doesn’t apply. Unfortunately, browsers don’t differentiate between first- and third-party JavaScript, giving it the same access to resources, content, or any sensitive information provided by users — regardless of whether it came from an in-house team or an external service. In other words, a third party can access anything your own code can, leaving sensitive customer data at risk of being exposed (e.g. credit card details, PII, and cookie information).

Being able to manage and monitor your scripts is key to ensuring the performance, security, and reliability of your website. Instart gives you back control where it’s needed, right in the browser. The way modern websites are built means relying on first-party and third-party code to give your customers great experiences, but unless these third-party scripts work perfectly, your site can be vulnerable to security threats or suffer from degraded site performance. Learn how Instart can help you deliver a safe, reliable experience every time someone visits — no exceptions.