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Where to
JavaScript is the programming language of HTML and the Web. In HTML, JavaScript must be inserted in the <script>
container tag.
Example
<script>
window.alert("This JavaScript Works!");
</script>
Also, remember that you can place any number of <script>
tags in an HTML document.
Where does the <script>
tag go?
The <script>
tag can be placed in the <head>
or the <body>
.
JavaScript in the <head>
In this example, the JavaScript is placed in the <head>
section of the document. A function onClicked is created, which is called when a button is pressed.
<!DOCTYPE html>
<html>
<head>
<script>
function onClicked() {
window.alert("Hi, there!");
}
</script>
</head>
<body>
<h1>JavaScript Testing</h1>
<button type="button" onclick="onClicked()">Try it</button>
</body>
</html>
JavaScript in the <body>
Here, the JavaScript is placed in the . The function onClicked is created and is set to be fired when the button is clicked.
<!DOCTYPE html>
<html>
<body>
<h1>JavaScript Testing</h1>
<button type="button" id="buttonClicked">Try it</button>
<script>
document.getElementById("buttonClicked").onclick = onClicked;
function onClicked() {
window.alert("Hi, there!");
}
</script>
</body>
</html>
External Scripts
Scripts can also be placed in external files. Let's create a file script.js.
script.js
window.alert("Hi!");
This script can be included in an HTML document as so:
<!DOCTYPE html>
<html>
<body>
<script src="script.js"></script>
</body>
</html>
Hi! will still be alerted when the page is rendered. Remember, you do not need to include <script>
tags in JavaScript files (the files which have the extension .js).
More Information:
Yahoo recommends placing scripts at the bottom. This is elaborated here, with the reason for this recommendation.