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 âHello Worldâ document using JavaScript might look like Example 13-1.
<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 youâd 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 ...
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