While learning development and programming skills, the use of good practices should be encouraged. JavaScript detractors often say that JavaScript is a rather poor choice of a programming language. By separating your site’s structure using HTML, its behavior through JavaScript, and its presentation through CSS, the JavaScript programming itself can be productive and enjoyable.
A typical web page contains the HTML code that creates the structure of the page, the CSS that controls its appearance, and the JavaScript that makes it function properly. It is often much easier to maintain and debug such a page if the JavaScript is isolated from the HTML, which is also separate from the CSS.
Developers should avoid practices such as the use of embedded styles within HTML elements, as it is an easy habit to fall into when your pages’ HTML, CSS and JavaScript code all reside on the same document.
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