Datasheet

Chapter 1: Introduction to JavaScript

On Windows, Internet Explorer comes pre - installed. You can choose to upgrade to the latest version or

leave it the way it came. You should then also download Firefox from

http://www.getfirefox.com

and Safari from

http://www.apple.com/safari/ . Google Chrome can be downloaded at

http://chrome.google.com and Opera from http://www.opera.com .

On Mac, you ’ ll want to download Firefox from the same location, and, of course, Safari comes

pre - installed. For testing Internet Explorer, we suggest you run copies inside a Windows VMWare or

Parallels image right on your desktop.

In Chapter 21, I ’ ll talk more about tools that can assist you in debugging your applications inside a

browser. For now, just make sure you can load a test page on your computer using whatever browser

you have handy at least by using the file:// technique mentioned earlier.

Your First JavaScript Application

This chapter provides a lot of background on the history and role that JavaScript plays in development,

but no introduction on a programming language would be complete without one bare - bones example.

Remember that all the examples in this book can be found online at

http://wroxjavascript.com .

There are several ways to augment a web page with JavaScript. One is to use the HTML tag

< script > to

indicate a portion of the page for script. This is known as a script block . When a browser spots a script

block in a page, it does not draw its contents to the page. Instead, it “ parses ” its contents as a script block

in the order that it appears . Generally speaking, if there are two script blocks on a page, the top one will

execute first. You are allowed to put script blocks in the

< head > area of the page and also in the < body >

area. Blocks in the header execute before ones in the body.

I ’ ll talk more about

< script > tags in Chapter 3 because there are a few more things you should know

about them. For now, take a look at the HTML page that follows with some in - line JavaScript code.

< html >

< body >

< h1 > Hello World! < /h1 >

< script type=”text/javascript” >

var today = new Date();

document.write(“ < p > Today is: “ + today.toString() + “ < /p > ”);

< /script >

< /body >

< /html >

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