Nick Sims Scripting Languages

Dynamic Web Sites Static websites are old fashioned Dynamic websites are preferred and they are easier to maintain once they “go live” on the Internet

Types of scripting languages HTML (what does it stand for?) (Hyper Text Markup Language) JavaScript VBScript

Nature of Language Object-oriented languages: the code is broken into objects Each object knows what it can do (how what and how it can interact) and is a self-contained module Event driven language – the code is broken into handling events i.e. An action – mouse click, key pressed or transmission of data

Objects and methods Each object has properties and these properties have values. A method is how an object can carry a task out <script> hw=“Hello World” document.write(hw.toUpperCase()) </script> The output is HELLO WORLD on screen

Security As code is being executed this is a possible entry route for hackers making the client’s computer system and the web site vulnerable Also unscrupulous website owners could read the contents of a client’s computer Such as data mining, opening applications and reading other browser windows

Including scripts inside HTML HTML is interpreted by the browser and executed line by line Functions such as script functions can be placed anywhere as they are not run until they are called Script needs to be placed between <script> and </script> tags for the browser to know it is not interpreting HTML

Scripting Language Constructs Variables and operators Variables hold data Operators can be used to perform calculations and assign values to variables Loops – piece of code executed repetitively Decision making (known as selection) Functions – written separately, which can be called and executed whenever required Parameter – where a value in a bracket of passed to the function to use