Optimization of third-party scripts -
You can learn more about how you can use WebPageTest to test the performance impact of third-party scripts. This feature allows you to get detailed insights into third-party script requests on a page.
Note: Google Chrome version 80 has removed this feature announcing no replacement. For now, you must sort external scripts manually until Google addresses this issue. The async attribute forces the browser to continue parsing the rest of the HTML document till the script gets downloaded.
Once the script finishes downloading, it pauses parsing the HTML document to run the script. WP Rocket is the easiest way to delay JavaScript files and let your page load faster.
jQuery, Modernizr, Underscore. Warning: Self-hosted scripts can go out of date and not work as intended. Many WordPress themes and plugins load a lot of unnecessary scripts that you may never use.
This helps older plugins and themes maintain backward compatibility with the old version of jQuery. Ask yourself whether your website really needs a slider or a date formatting script.
Connecting to external domains to download third-party scripts can take an excessive amount of time, especially if your users are on slow networks. DNS lookups, redirects, and any round-trips for loading each third-party script can add up to significant delays. You can use browser resource hints to establish a connection with the external domain hosting the third-party script at the start of page load itself.
There are many resource hints, but the ones that are helpful here are dns-prefetch or preconnect. You can lazy-load these embedded resources to speed up your page load. You can use WP Rocket to enable lazy-loading on your WordPress website.
Note: WordPress 5. Tag managers allow you to bundle multiple third-party scripts or tags and manage them all from a single source.
Using a tag manager wisely can help you minimize the performance hits of loading third-party scripts. While you can load third-party scripts asynchronously, the browser still needs to parse and execute them individually.
This might mean requesting additional data during the page load. Tag managers solve this problem by reducing the number of requests down to one. Google Tag Manager GTM is the most popular solution to manage tags. It loads itself and all its tags asynchronously so that the browser renders a page without pause.
The Google Tag Manager for WordPress plugin is a simple way to integrate GTM on WordPress sites. Other tag managers that you can look into are Adobe Experience Platform Launch , Ensighten , and Qubit.
Warning: Use tag managers like GTM judiciously. While it reduces the cost of loading third-party scripts, its simplicity also opens it to abuse by anyone with the credentials to add tags.
Some tags can also introduce a chain of requests that can bring your site to a crawl. A performance budget is a self-imposed limit to count the total number of requests and size of scripts, images, etc. For more, check out the list of all the supported resource types and metrics.
Discussing the exact method to set performance budgets is beyond the scope of this article, but you can read more about how to do it in Lighthouse docs. Third-party scripts have become a crucial part of most websites today.
Some topics discussed in this article may not be easy to grasp right away. I suggest you go through them once again. Understanding the performance impact of third-party scripts and how you can manage them will help you regain control over your page load performance.
WP Rocket can easily help you reduce the impact of third-party code. Get it now, and test the improvement right away! If you have questions about any of the points discussed in this article, please feel free to leave a comment. Salman Ravoof is a self-taught web developer, writer, and creator.
Apart from tech, he finds science, philosophy, and food exciting. Learn more about him on his website , and connect with Salman on Twitter. Thx for the post! Really interesting to see what you can do with WebPageTest.
Didn't know that. I did the test myself and found that the loading of "stackpath. css" in my header as a stylesheet is slowing the website initial load a lot. The difference between async and defer is when they start executing the scripts. Scripts with the async attribute execute at the first opportunity after they finish downloading and before the window's load event.
This means it's possible and likely that async scripts will not be executed in the order in which they appear in the HTML. It also means they can interrupt DOM building if they finish downloading while the parser is still at work. Scripts with the defer attribute execute after HTML parsing is completely finished, but before the DOMContentLoaded event.
defer guarantees scripts will be executed in the order they appear in the HTML and will not block the parser. Use async if it's important to have the script run earlier in the loading process. Use defer for less critical resources.
A video player that's below-the-fold, for example. Using these attributes can significantly speed up page load. For example, Telegraph recently deferred all of their scripts , including ads and analytics, and improved the ad loading time by an average of four seconds. You can save — ms by establishing early connections to important third-party origins.
When the request for a resource from the pre-connected origin is made, the download starts immediately. Establishing a connection involves the DNS lookup and TCP handshake, and for secure origins, TLS negotiations.
dns-prefetch instructs the browser to only resolve the DNS of a specific domain before it has been explicitly called. Browser support for dns-prefetch is slightly different from preconnect support , so dns-prefetch can serve as a fallback for browsers that don't support preconnect.
Use separate link tags to implement this safely:. Embedded third-party resources can be a big contributor to slow page speed when constructed poorly. If they aren't critical or are below the fold that is, if users have to scroll to view them , lazy loading is a good way to improve page speed and paint metrics.
This way, users will get the main page content faster and have a better experience. One effective approach is to lazy-load third-party content after the main page content loads. Ads are a good candidate for this approach. Ads are an important source of income for many sites, but users come for the content.
By lazy loading ads and delivering the main content faster, you can increase the overall viewability percentage of an ad. Thankfully, there are a number of free resources that you can use to identify and measure costly third-party scripts. The first step to solving the third-party resource problem is to identify and measure the most impactful ones.
It lets you instantly see how impactful the third-party scripts on your site are. In the example above, you can see that they blocked the Main Thread for 2, ms.
You can dig deeper by going through the list of all third-party code that is executed on your site. The great thing is that PSI sorts it by Main-Thread Blocking Time. This evaluation allows you to focus on the most impactful ones and start working on them.
Going to the Domain section, you will see a thorough breakdown by the number of requests and bytes for each domain:. WebPageTest also has a waterfall chart where you can see all the render-blocking resources and allocate all third-party scripts and their execution time:.
Then you can specify the domains you would like to block by entering them in the forms below. Test again and see if there is any improvement. Clicking the record button and re-loading your page presents you with a waterfall similar to the one in WebPageTest :.
com contributes Using this knowledge, you can more accurately pinpoint problem areas and begin investigating with some evidence behind you. This is a great way to see what the absence of a particular asset would have on the current page. There are several optimization techniques that you might want to try when working with third-party scripts:.
A single web page is constructed of different resources. However, not all of them are critical for providing the best user experience right from the start. Users want to see content being painted quickly and experience a website that becomes interactive immediately.
To retain your visitors longer, your site needs to be fast and interactive. Or at least it needs to give that impression. This is where lazy loading comes into play. Typically used in the context of images , you can lazy load defer third-party resources as well, making them load only when necessary.
This way, you can focus on serving the most critical content above the fold first, and load everything else once the visitor scrolls down. If they lazy load it, it will be served only when a visitor scrolls down to it. NitroPack offers a JavaScript lazy loading feature that works based on user interaction and it is enabled by default with our Ludicrous mode.
It prioritizes HTML and CSS files, while deferring JS files, resulting in faster content painting and a better user experience. On top of that, you can fine-tune the JavaScript feature by listing scripts that you want to exclude from optimizations and scripts that must be delayed:.
Synchronously loaded scripts delay DOM construction and block rendering. The async and defer attributes allow the browser to parse the HTML while loading the render-blocking scripts in the background. This way, script downloads don't block DOM construction and page rendering, resulting in faster loading and happier visitors.
Put simply, scripts that need the DOM or whose order is important should use the defer attribute. Conversely, ad, analytics, and other independent scripts should generally use async.
Optimization of third-party scripts Optlmization leads Natural muscle preservation small team of web performance experts zcripts data scientists Optimization of third-party scripts Scirpts Technologies. Portion control tracker operations team is Optimization of third-party scripts to go. Your website Opimization be using more third-party services than Optimizatlon realize. These services use requests to external hosts not servers you control to deliver JavaScript framework libraries, custom fonts, advertising content, marketing analytics trackers, and more. You cannot always anticipate what you cannot control. Even if you cannot prevent all third-party requests, web designers can make choices that will have an impact. In this article, we will review what third-party resource requests are, consider how impactful they can be to the user experience, and discuss common optimization strategies to reduce the impact on the user experience. Avoid the Optimizaton pitfalls of Optikization third-party scripts to improve load times and user Optimizatiin. Milica Mihajlija Scripys GitHub Homepage. If a third-party Top magnesium products is slowing Optimiztion your page scropts, you have two options Natural muscle preservation improve performance:. This post explains how to optimize the loading process of third-party scripts with the following techniques:. Because synchronous scripts delay DOM construction and rendering, you should always load third-party scripts asynchronously unless the script has to run before the page can be rendered. The async and defer attributes tell the browser that it may go on parsing the HTML while loading the script in the background, and then execute the script after it loads.
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