Just wanted to clarify that you are not comparing apple to apples. First of all, PHP is a programming language while JavaServer Pages (JSP) and ASP. NET are not. Let's get that straightened out first.
JSP is a technology that helps software developers create dynamically generated web pages based on HTML, XML. It uses the Java programming language.
ASP. NET is a server-side web application framework, and most developers using it use the C# programming language to code with it.
Also worth mentioning, a lot of people here make mentioned of PHP being open sourced as a differentiation among the three... ASP. NET is also a series of open source projects, look here (Open Source) or here (aspnet/Home) or here (Open Source Foundation for the .NET Community).
Now that we got that out of the way... perhaps the question should be about PHP, Java and C# or about their more popular web frameworks such as Laravel or CakePHP for PHP, Spring for Java and ASP. NET for C#.