Introduction to PHP & Server-Side Scripting

Gaining foundational expertise in php scripting language cs508 is vital for understanding modern dynamic web application development and distributed computing architectures. In Lecture 35 of the Virtual University CS508 syllabus, students examine the architectural principles, historical evolution, syntax rules, and dynamic typing mechanisms of PHP. Created in 1994 by Rasmus Lerdorf as Personal Home Page tools, PHP has evolved into the recursive acronym PHP: Hypertext Preprocessor, becoming one of the most widely deployed server-side scripting languages globally. The lecture contrasts server-side execution with client-side script processing. In the client-server architecture, a web browser issues an HTTP request for a web resource. The web server executes the embedded PHP code through its PHP parsing engine, interprets all program logic, interacts with file systems or databases, and returns pure HTML to the client browser. Consequently, the client never receives the original source code, ensuring business logic protection and cross-browser consistency. The curriculum analyzes PHP script delimiters, focusing on standard tags that embed PHP instructions seamlessly within HTML documents. PHP statements terminate with semicolons, and code comments follow C, C++, and Unix shell comment conventions. Program output is generated primarily through echo and print constructs. The lecture investigates PHP variable syntax, highlighting that variable identifiers start with a dollar sign prefix and are strictly case-sensitive. When students ask whether PHP is a statically or dynamically typed language, the handouts confirm that PHP is a dynamically typed language: variables lack explicit type declarations and bind to types dynamically at runtime based on assigned values. The language supports eight data types, including boolean, integer, float, string, array, object, resource, and NULL. The lecture demonstrates dynamic type juggling and coercion, showing how strings with leading numeric digits evaluate as numbers in arithmetic expressions, while non-numeric strings evaluate to zero. Explicit casting enables type conversions using cast operators. Preparing with official handouts, past papers, and solved MCQs on VUSIGMA ensures superior exam performance.