The <script> Tag
In HTML, JavaScript code is inserted between <script> and </script> tags.Example
<script>document.getElementById("demo").innerHTML = "My First JavaScript";
</script>
JavaScript Where To
The <script> Tag
In HTML, JavaScript code is inserted between <script> and </script> tags.Example
<script>document.getElementById("demo").innerHTML = "My First JavaScript";
</script>
Old JavaScript examples may use a type attribute: <script type="text/javascript">.
The type attribute is not required. JavaScript is the default scripting language in HTML.
JavaScript Functions and Events
A JavaScript function is a block of JavaScript code, that can be executed when "called" for.For example, a function can be called when an event occurs, like when the user clicks a button.
You will learn much more about functions and events in later chapters.
JavaScript in <head> or <body>
You can place any number of scripts in an HTML document.Scripts can be placed in the <body>, or in the <head> section of an HTML page, or in both.
JavaScript in <head>
In this example, a JavaScript function is placed in the <head> section of an HTML page.The function is invoked (called) when a button is clicked:
Example
<!DOCTYPE html><html>
<head>
<script>
function myFunction() {
document.getElementById("demo").innerHTML = "Paragraph changed.";
}
</script>
</head>
<body>
<h2>Demo JavaScript in Head</h2>
<p id="demo">A Paragraph</p>
<button type="button" onclick="myFunction()">Try it</button>
</body>
</html>
JavaScript in <body>
In this example, a JavaScript function is placed in the <body> section of an HTML page.The function is invoked (called) when a button is clicked:
Example
<!DOCTYPE html><html>
<body>
<h2>Demo JavaScript in Body</h2>
<p id="demo">A Paragraph</p>
<button type="button" onclick="myFunction()">Try it</button>
<script>
function myFunction() {
document.getElementById("demo").innerHTML = "Paragraph changed.";
}
</script>
</body>
</html>
External JavaScript
Scripts can also be placed in external files:External file: myScript.js
function myFunction() {document.getElementById("demo").innerHTML = "Paragraph changed.";
}
External scripts are practical when the same code is used in many different web pages.
JavaScript files have the file extension .js.
To use an external script, put the name of the script file in the src (source) attribute of a <script> tag:
Example
<script src="myScript.js"></script>Thank You For Learning!
