Make sure that the HTML document has a PHP extension (i.e. Notepad on Windows and TextEdit on Mac are the native text editors that ship with the... 2. mypage.php). To add a variable, simply do something like this: let x = 5; console.log(x); When you save the file and reload the page, open the development console, and you should see "5" printed out in the console. Build a simple website using HTML, CSS, and JavaScript. Solution 1 Javascript was actually developed as a client side language to perform basic computation and validation before sending the information to server. However, if your script needs to run at a certain p… HTML is the language in which most websites are written. into an HTML element with id="demo": Tip: You can learn much more about JavaScript in our JavaScript Tutorial. Please help us continue to provide you with our trusted how-to guides and videos for free by whitelisting wikiHow on your ad blocker. wikiHow's Content Management Team carefully monitors the work from our editorial staff to ensure that each article is backed by trusted research and meets our high quality standards. JavaScript is one of the most popular modern web technologies! While using W3Schools, you agree to have read and accepted our, Defines an alternate content for users that do not support client-side Do you want to use Internal code in JavaScript? {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/f\/f5\/864267-1.jpg\/v4-460px-864267-1.jpg","bigUrl":"\/images\/thumb\/f\/f5\/864267-1.jpg\/aid864267-v4-728px-864267-1.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"