August 2012
Beginner
583 pages
16h 1m
English
Content preview from Learning PHP, MySQL, JavaScript, and CSS, 2nd EditionBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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JavaScript and HTML Text
JavaScript is a client-side scripting language that runs entirely
inside the web browser. To call it up, you place your JavaScript code
between opening <script> and
closing </script> HTML tags. A typical
HTML 4.01 “Hello World” document using JavaScript might look like Example 13-1.
Example 13-1. “Hello World” displayed using JavaScript
<html>
<head><title>Hello World</title></head>
<body>
<script type="text/javascript">
document.write("Hello World")
</script>
<noscript>
Your browser doesn't support or has disabled JavaScript
</noscript>
</body>
</html>Note
You may have seen web pages that use the HTML tag <script language="javascript">, but that
usage has now been deprecated. This example uses the more recent and
preferred <script
type="text/javascript">.
Within the <script> tags is
a single line of JavaScript code that uses the JavaScript equivalent of
the PHP echo or print commands, document.write. As you’d expect, it simply
outputs the supplied string to the current document, where it is
displayed.
You may have also noticed that, unlike with PHP, there is no
trailing semicolon (;). This is because
a newline serves the same purpose as a semicolon in JavaScript. However,
if you wish to have more than one statement on a single line, you do need
to place a semicolon after each command except the last one. And of
course, if you wish, you can add a semicolon to the end of every statement
and your JavaScript will work fine.
The other thing to note in this example ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.