With the rapid evolution of web services and technologies, the number of Internet users is constantly increasing. Since many people suffer from various temporary or permanent disabilities and deficiencies, advanced web development practices should be applied to provide content that is accessible for all. The importance of web accessibility is being recognized by an increasing number of web designers and developers. W3C provides useful guidelines to ensure content accessibility. The accessibility support implemented in modern software tools and web sites should be clearly indicated so people living with disabilities can easily identify them. HTML5 markup also supports accessibility through advanced structuring elements, metadata, and Accessible Rich Internet Applications (ARIAs). Web accessibility techniques are not limited to the visually impaired or people with other disabilities. In fact, they also ease mobile access to web content and improve overall web page quality.