JavaScript® Bible, Sixth Edition

Foreword

As JavaScript's creator, I would like to say a few words about where JavaScript has been, where it is going, and how the book you're holding will help you to make the most of the language.

JavaScript was born out of a desire to let HTML authors write scripts directly in their documents. This may seem obvious now, but in the spring of 1995 it was novel and more than a little at odds with both the conventional wisdom (that HTML should describe static document structure only) and the Next Big Thing (Java applets, which were hyped as the one true way to enliven and extend web pages). Once I got past these contentions, JavaScript quickly shaped up along the following lines:

• "Java-lite" syntax. Although the "natural language" syntax of HyperTalk was fresh in my mind after a friend lent me The Complete HyperCard Handbook by some fellow named Goodman, the Next Big Thing weighed heavier, especially in light of another goal: scripting Java applets. If the scripting language resembled Java, then those programmers who made the jump from JavaScript to Java would welcome similarities in syntax. But insisting on Java's class and type declarations, or on a semicolon after each statement when a line ending would do, were out of the question—scripting for most people is about writing short snippets of code, quickly and without fuss.

• Events for HTML elements. Buttons should have onClick event handlers. Documents load and unload from windows, so windows should have onLoad and onUnload handlers. ...