What is JavaScript?
JavaScript was designed to add interactivity to HTML pagesJavaScript is a scripting languageA scripting language is a lightweight programming languageJavaScript is usually embedded directly into HTML pagesJavaScript is an interpreted language (means that scripts execute without preliminary compilation)Everyone can use JavaScript without purchasing a license
What can a JavaScript do?
JavaScript gives HTML designers a programming tool - HTML authors are normally not programmers, but JavaScript is a scripting language with a very simple syntax! Almost anyone can put small "snippets" of code into their HTML pagesJavaScript can put dynamic text into an HTML page - A JavaScript statement like this: document.write("<h1>" + name + "</h1>") can write a variable text into an HTML pageJavaScript can react to events - A JavaScript can be set to execute when something happens, like when a page has finished loading or when a user clicks on an HTML elementJavaScript can read and write HTML elements - A JavaScript can read and change the content of an HTML elementJavaScript can be used to validate data - A JavaScript can be used to validate form data before it is submitted to a server. This saves the server from extra processingJavaScript can be used to detect the visitor's browser - A JavaScript can be used to detect the visitor's browser, and - depending on the browser - load another page specifically designed for that browserJavaScript can be used to create cookies - A JavaScript can be used to store and retrieve information on the visitor's computer
