The war between PHP and ASP.NET has been going for years. Users are confused about choosing one from these two. PHP, created by Rasmus Lerdorf, is server-side scripting language designed for the web. PHP is designed for web development and can be embedded into HTML. ASP.NET, developed by Microsoft, is a server-side web application framework used fro creating dynamic web sides, web applications and web services.
There are many differences and similarities between the two. One of which is PHP being free, and open-source while ASP.NET is proprietary. The other, is compatibility.
To save you from confusion, here is an infographic of PHP vs ASP.NET: