JavaScript and JQuery: Interactive Front-End Web Development

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BASIC JAVASCRIPT INSTRUCTIONS

In this chapter, you will start learning to read and write JavaScript. You will also learn how to give a web browser instructions you want it to follow.

THE LANGUAGE: SYNTAX AND GRAMMAR

Like any new language, there are new words to learn (the vocabulary) and rules for how these can be put together (the grammar and syntax of the language).

GIVING INSTRUCTIONS: FOR A BROWSER TO FOLLOW

Web browsers (and computers in general) approach tasks in a very different way than a human might. Your instructions need to reflect how computers get things done.

We will start with a few of the key building blocks of the language and look at how they can be used to write some very basic scripts (consisting of a few simple steps) before going on to look at some more complex concepts in subsequent chapters.

STATEMENTS

A script is a series of instructions that a computer can follow one-by-one. Each individual instruction or step is known as a statement. Statements should end with a semicolon.

We will look at what the code on the right does shortly, but for the moment note that:

• Each of the lines of code in green is a statement.
• The pink curly braces indicate the start and end of a code block. (Each code block could contain many more statements.)
• The code in purple determines which code should run (as you will see on p149).

JAVASCRIPT IS CASE SENSITIVE

JavaScript is case ...