HTML5 and CSS3 are two of the three most important technologies when developing websites. HTML, short for HyperText Markup Language is used not only for creating websites, but also for developing web applications and mobile applications. On the other hand, CSS3 is used for modifying the visuals of any HTML pages. The sheet is written separately and linked to the main HTML pages, meaning that the HTML page no longer has to constantly be modified to change the layout of the website. It is a must have technology for any developer. This is a free course with a MOOC List coupon.