2. HTML. We write HTML in files that end with the .html extension (like homepage.html).. To write HTML and CSS code, you’ll want to install a code editor.Nowadays, one of the most popular free ...

Then, the classNames for the form elements are swithced with JavaScript. Marko also uses JavaScript to preloaded the custom images. Here's an example of his technique from the Nacional news magazine: ...

HTML and CSS form the basic coding languages for web design and development. If you need to perform any kind of activity related to web manipulation, a working knowledge of these two is essential.

AFAIK, CSS cannot affect the DOM tree. So, display: none just says the element should not be displayed, not that it should cease to exist. Style/structure separation and all that.