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JavaScripts in the body section will be
executed WHILE the page loads.
JavaScripts in the head section will be
executed when CALLED.
Where to Put the JavaScript
JavaScripts in a page will be executed immediately while the
page loads into the browser. This is not always what we want.
Sometimes we want to execute a script when a page loads, other
times when a user triggers an event.
Scripts in the head section: Scripts to be executed
when they are called, or when an event is triggered, go in the
head section. When you place a script in the head section, you
will ensure that the script is loaded before anyone uses it.
<html>
<head>
<script type="text/javascript">
....
</script>
</head>
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Scripts in the body section: Scripts to be executed
when the page loads go in the body section. When you place a
script in the body section it generates the content of the page.
<html>
<head>
</head>
<body>
<script type="text/javascript">
....
</script>
</body>
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Scripts in both the body and the head section: You can
place an unlimited number of scripts in your document, so you
can have scripts in both the body and the head section.
<html>
<head>
<script type="text/javascript">
....
</script>
</head>
<body>
<script type="text/javascript">
....
</script>
</body>
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Using an External JavaScript
Sometimes you might want to run the same JavaScript on
several pages, without having to write the same script on every
page.
To simplify this, you can write a JavaScript in an external
file. Save the external JavaScript file with a .js file
extension.
Note: The external script cannot contain the <script>
tag!
To use the external script, point to the .js file in the
"src" attribute of the <script> tag:
<html>
<head>
<script src="xxx.js"></script>
</head>
<body>
</body>
</html>
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Note: Remember to place the script exactly where you
normally would write the script! |
