Science is where you measure, analyze, and develop theories. Computer science in particular is about the design of algorithms and systems for their implementation, such as compilers and interpreters.
Programming is a means of operating computer systems. Sometimes you have to operate computers to do computer science, but not always (for example algorithm design is very mathematical.)
there is meaningful overlap, certainly
and also, not all programming is science, certainly
Feel free to enlighten us as to what comp sci and Web dev are, and why they share nothing in common. Please.