Browser Compatibility Testing (also known as Cross-Browser Testing) is to verify that web pages display and function correctly across different web browsers, such as Chrome, Firefox, Safari, Opera and Internet Explorer (now replaced with Microsoft Edge). This also extends to mobile devices and tablets, many of which use their own type of browser. Not all browsers or browser versions are compatible with some of the layout and styling elements, such as some of those introduced to CSS in recent years. Different browsers also have different ways of rendering certain fonts and symbols.