Simply put, Link Preload is all about offering the developers the capacity to define the custom loading logic without having to compromise the performance faced by the script-based resources loaders. In a common man’s terms, the Link Preload ‘directs’ the browsers to begin fetching a specific resource as the user as authors understand that such an assistance for the browser is required.
What is Meant By Link Preload?
Basically, the concept of Pre-load is a latest web standard inorder to enhance the performance by offering a better ‘load control’ to the web developers. Thus, you can say that it offers the developers the feature to define custom loading logic, and as mentioned previously without having to suffer the script-based resource loader penalty otherwise faced.
It was in the year 2016 that this brand new web standard was introduced by Youv Weiss for Chrome. This was designed to allow new pathways for quicker load times. Today, Preloading is one of the leading resource prioritization techniques as applied by some of the leading sites in the world. This has grown in its popularity because it helps enhance the load time and also offers a better user experience.
What is Resource Prioritization?
First, we need to understand what is meant by ‘manual’ Resource Prioritisation. This is mainly ‘prompting’ the browser to conduct the process of page loading. But before a developer begins with the process, there are a few basics of the concept that you need to take care of. Here, you need to know that the browsers usually figure out the specified assets to request and in a certain order as well.
Once the resource has been downloaded by the browser, a priority has been assigned as such: highest, high, medium, low, or lowest. So, what do the priority depends up on? Well, it depends upon the resource type such as the : image, text, stylesheet, video and script. ALso, the placement of the resource reference is also a part of the priority within the document.
As and when you are selecting the assets to pre-load, it is important to be mindful of the render-blocking resources and avoid the browsers from having to download them first. If not done in such a manner, you can be facing the risk of displaying a blank page instead of quick loading.
Understanding the Link Preload
While one can explain the process of link preload to be a resource fetcher, nevertheless it is a lot more different as compared to other techniques such as Preconnect or Prefetch. This is because the aspect of Pre-load is not just a ‘hin’ but also declarative in nature. This implies to the fact that the browsers have to work hard to ‘hunt’ the resources that are important for the page experience.
The resources can be pre-loaded by adding a link tag along with rel=”preload” to the head of your HTML document, like below
<link rel=”preload” as=”script” href=”critical.js”>
The good news is that, most common browsers support the process of Pre-loading. This is to enable the developers and the site owners to acquire quicker load time and offer the users a limit-free experience.
How Important is Link Pre-load?
The aspect of Link Preload is quite important in the process of web development today. This is because it offers you a more granular control in order to define the concept of custom loading logic. Now, if your site requires it at all, this entirely depends upon the results of the audit.
The other interesting aspect to take into account is that the process of preload can interfere with the right rendering of the page. This usually occurs in the case of non-important files and in larger quantities. This happens because instead of concentrating on the necessary render-blocking resources, the browser gets busy with the low-priority files instead.
How Is it Different from Prefetch?
At the start of its launch, most users had confused link preload to Prefetch directive, which was available previously. However, both are quite different; as Pre-fetch aims mainly on the resource that will mostly grow important for navigation in the future. This implies to those navigations that occur after the current page. Now, one needs to bear in mind that Preload is all about dealing with a resource required for the current navigation.
The Web Page Elements that Can be Pre-loaded
Now let us take a look at the resources that can be pre-loaded by the Link Preload:
- Sound and music files
- Video (MP4, MP3, WebM)
- Audio WebVTT tracks
- JavaScript files
- CSS style sheets
- Web fonts (TTF, EOT, WOFF, WOFF2)
- Images (AVIF, WebP, JPG, and JPEG, or PNG)
- XHR and fetch API requests
- Web workers
- Multimedia embed and object requests
CONCLUSION
This is all that we have at the moment about What is Link Preload and Its Importance. Do share how you liked the article and we would love to hear from you.
