JavaScript is a scripting language that was developed by Sun Microsystems. JavaScript is now a standard programming language used in web browsers to create interactive web pages. JavaScript is most commonly used to add interactivity to websites. It is often embedded in HTML documents to provide dynamic behavior, such as changing content (e.g., text) displayed on a website page based on user actions. The first version of JavaScript was released in 1995 and was named LiveScript. In 1997 Netscape introduced its own implementation of JavaScript called JavaScript 1.0. Since then, JavaScript has become widely adopted and is now a de facto standard for client-side scripting. SEO is an important part of any website, and it's a good idea to optimize your JavaScript for a high rank in search results. You can do this by minifying your JavaScript, deferring its loading, reducing the number of HTTP requests, removing unnecessary script tags from the page (and from individual files), and consolidating files into one file if they're small enough to do so, and more. Minify JS and CSS. Minifying your JS and CSS is a good way to get rid of those extra bytes. This can be done with a minifier, which will remove unnecessary characters from your source code without affecting its functionality. The minification process works by removing white space and comments, as well as shortening variable names where possible. For example: <-- uses var names, but removes extra spaces <-- shortens variables var $div = document.getElementById("myDiv"); var v_d__e___ = document .getElementById( "m_i_d" ); It's important to note that the process doesn't change the functionality of your code; in fact, you could still run this version through an interpreter if it were necessary (although we wouldn't recommend it). Defer loading of JavaScript In the HTML code, you can use the defer property of the tag to tell the browser to load your script asynchronously. This is useful for scripts that are not critical to the initial rendering of a page, but rather enhance it with additional functionality and features. Deferring these scripts allows them to be loaded outside of normal download priority, so they don't block content from displaying right away. However, if you try using this method for major scripts that need all their functionality immediately—such as your site's main navigation menu—it won't work properly because those require quick loading times. The downside of implementing defer is that it isn't supported by all browsers; it only works in Firefox 3+ (and later), Internet Explorer 10+ (and later), Safari 5+, and Chrome 14+. Reduce the number of HTTP requests One way to reduce the number of HTTP requests is to combine all your CSS and JavaScript files into one file. If you have more than a few lines of code, this can be a big help in reducing your page weight. If you have many small files, though, combining them into one large file may not be an option for you because it will require extra time for a user’s browser to download it all at once. Remove unnecessary JavaScript, CSS, and HTML Luckily, you don't need to be a master coder to optimize your JavaScript for search. You just have to follow a few simple rules: Remove unused CSS. Remove unused HTML. Remove unused JavaScript. Remove unnecessary comments and whitespace from the code (e.g., “//” or “/* */”). Remove unnecessary line breaks, semicolons, parentheses, braces and commas in the JavaScript file so that they don't break anything else in your project when it's minified by tools like Google Closure Compiler or UglifyJS 2 on build servers such as Jenkins CI server or TravisCI server/etc… Consolidate files. It's a good idea to consolidate your JavaScript files into a single file. This can be done with a build system like Grunt or Gulp, which allow you to use functions like concatenation and minification. If you don't want to learn about building systems, there are many services that will automatically do this for you. One of the easiest ways is using Cloudflare (free plan available). Simply upload all your files through their interface, then use the "minify" option under their Settings tab. They'll give you a custom URL for each file on their servers, which then minimizes all of those files before sending them back to your visitor's browser. This makes it much faster for them because they only have one request from Cloudflare instead of multiple requests from different domains around the web. Another option is JSPACK (paid), which is similar but offers more functionality and control over exactly how much code gets compressed/removed in order to achieve better optimization performance results than other compression tools would provide by default due to specifically targeted needs specific situations where some applications might require access certain pieces data contained within JavaScript files contained within specified directory structure located somewhere else entirely across the internet... In addition, a and custom graphics can be created and placed within your HTML5 website/app to give it that extra bit of pizzazz that will ensure people remember you. custom logo Title and Description! Pages written in JavaScript need to have many of the same SEO meta tags as pages written in HTML and CSS. Both the title and the description are essential components of an effective SEO strategy for meta tags. Web browsers will show the title SEO meta element, and search engines will normally utilize this information to construct titles for pages that they have indexed. Even though it isn't shown in web browsers, the description SEO meta element can be used by search engines to generate text snippets or descriptions for pages that have been indexed. There is no issue with defining the title and description SEO meta tags using JavaScript as it is a perfectly valid method. According to Google, it is even possible to employ JavaScript in order to modify both of these SEO meta tags. The bottom line is that the title and description meta SEO meta should be included on each and every page, including those that were written mostly in JavaScript. Get rid of comma-first coding styles and the like. First, let's get this out of the way: Please stop comma-first coding styles. They are a relic from the olden days when you could use commas in JavaScript to line up variable declarations and parameter lists. This is not valid anymore, and it should never have been legal in the first place! So how do you know if your code is using this style? It's easy to tell: Just look for multiple statements on the same line separated by commas (or blanks). See an example below: var x = 1; var y = 2; var z = 3; If your JavaScript looks like this—or worse yet, if it has blank lines in between each statement—it needs serious work! Fortunately, fixing these problems isn't too difficult once you know what they are and where to look for them. Load JavaScript from the bottom of the body (or footer). Remember that JavaScript should be loaded from the bottom of the body (or footer) and CSS from the top. This is because search engines will crawl your web pages by starting at the top and working their way down, so they tend to ignore anything they see after they’ve reached something like JavaScript or CSS files. You don’t have to worry about this if you’re using asynchronous loading techniques such as Ajax or deferred scripts since these methods load files in parallel but still allow for indexing. Put CSS at the top and JavaScript at the bottom. One of the easiest ways to optimize your page for search engines is by putting CSS at the top, and JavaScript at the bottom. This is because browsers will load CSS before JavaScript. To do this, you can add a tag to your index file that points to your stylesheet and then add another tag that references your JavaScript file. The reason why this is important is that if someone has JS disabled on their browser, they won't be able to use the site at all unless it's coded properly—which means putting CSS first! Compress components with gzip. Gzip is a compression algorithm that reduces the size of files. It can be used in both JavaScript and CSS, so you can use it for all the components you are using. You need to compress your code before uploading it to the CDN or hosting provider. Gzip reduction means that you won't have to download more bytes than what's needed when a user accesses your page. Gzip support is available in all modern browsers, so it's worth adding gzip at both ends: browser-side and server-side (NodeJS). To compress your content, you need to use gzip-based compression. You can use this tool to check if the files have been compressed correctly. Avoid CSS expressions. expressions are a feature introduced in CSS3 that allows you to use JavaScript within your stylesheets. You can use them to dynamically change the value of a property or even iterate over an array of values. CSS But here’s why you shouldn't use CSS expressions: they're difficult to optimize and make it harder for browsers to cache your stylesheet (which is bad). Furthermore, they may cause unexpected behavior on older browsers that don't support them. So avoid using them at all costs! Final words Using JavaScript in a way that optimizes for search is a great way to rank highly in search results. It's important to remember, however, that not all users have JavaScript enabled or the same amount of bandwidth available when browsing your site. These limitations can affect how well your website performs in search rankings if they aren't taken into account when optimizing JavaScript content for SEO purposes like any other type of content on your site would be treated by Google's algorithm.
