Modernizr is a JavaScript library which is designed to detect HTML5 and CSS3 features in various browsers, which lets JavaScript avoid using unimplemented features or use a workaround such as a shim to emulate them. Modernizr aims to provide this feature detection in a complete and standardized manner.
PHP: Hypertext Preprocessor is a server-side scripting language designed for Web development, but also used as a general-purpose programming language. PHP code may be embedded into HTML code, or it can be used in combination with various web template systems, web content management systems, and web frameworks.