JavaScript is a computer language that is commonly used to make modern web pages richer and much more engaging for users. The disadvantage of JavaScript is that it might slow down your website's performance. Alan Kent, the Developer Relations Engineer, discusses six JavaScript libraries and frameworks that might assist in improving your e-commerce site in the newest episode of Ecommerce Essentials.
The first is to keep the amount of JavaScript files on your website from growing too large. If care is not taken, the number of JavaScript files may grow, particularly if each UI component is stored in its own file. For websites that only support HTTP1, there are overheads for downloaded files. There are a lot of free tools available to determine if your website has an excessive quantity of JavaScript files. Enter the URL of a page on your public website to utilize PageSpeed Insights. The PageSpeed Insights report's opportunity section includes recommendations tailored to your website.
Tip #2: Avoid excessive DNS lookups
The second piece of advice is to avoid performing too many DNS lookups for the reference JavaScript file. There may be a DNS query overhead per domain name cited if JavaScript data is fetched from many domain names. It may cause a user's initial visit to your site to take longer. Reduce JavaScript execution time, according to reports like PageSpeed Insights. Using the network tab in Chrome developer tools to examine all the domain names mentioned may be a more reliable method. The DNA cache, unlike cookies, cannot be quickly erased, making DNS errors more difficult to discover.
Consider posting a copy of external reference JavaScript files on your site to decrease the number of DNS lookups. This is not always an easy option to make, because if you download a popular JavaScript library from a central location, it may already be in the browser cache owing to the visitor visiting another site that uses the same library. Putting a copy on your own site saves the DNS lookup but comes at the cost of having to download the material again.
Tip #3: Eliminate inefficient JavaScript
The next technique is to remove ineffective JavaScript from your website. Poor-quality JavaScript can cause web pages to load slowly, resulting in a negative user experience. PageSpeed Insights has identified a number of possibilities that may be linked to ineffective Javascript on your site. JavaScript execution time was once a significant portion of CPU time spent passing running JavaScript code. Remove render-blocking resources such as JavaScript, which may be performed before the page is drawn and the user TV content is reached. The document.write for the JavaScript function when used incorrectly, write can create substantial performance concerns on a page by blocking other actions.
Tip #4: Eliminate unused JavaScript
The majority of developers use jQuery UI or jQuery Mobile as is. This implies that the code contains all potential library components, even if you only require two or three. A similar problem can be seen in other JavaScript libraries. If you have the ability to control which components will be included in your library package, go for it. Your website will load considerably more quickly, giving your visitors a better experience.
Tip #5: Compress JavaScript files
Minifying code is not the same as obfuscating code, although they are both ways of making JavaScript more difficult to understand or smaller. Minification achieves the latter and can reduce file sizes, resulting in faster website load times. Line breaks, extra spaces, comments, and so on all contribute to the size of a JavaScript file and slow down page loading. This problem is easily solved by compressing the code. Machines, unlike humans, are not sensitive to the visual aesthetic of code. Even if all of your Javascript fits into a single string, computers can read and execute it.
Tip #6: Set appropriate cache durations for JavaScript code
Check that a JavaScript file is provided with the necessary cache expiration time headers as well. This saved browsers the time and effort of checking if JavaScript files in their cache were out-of-date, resulting in improved speed. Check to see sure your website is set up correctly. The HTTP response headers for downloaded JavaScript files may be checked using the Networking Tab in Chrome developer tools. Look for Cache Control and similar headers. Include the PageSpeed Insights Search Static Assets with an efficient cache policy option, which includes JavaScript files that may benefit from properly set cache headers.
Wrapping Up
As you can see, there are a variety of tools and strategies available to assist you in optimizing JavaScript code to reduce download and rendering times. You can use any of these standard optimization strategies to reduce page load times.
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