JavaScript is a Scripting Language:
A scripting language is a lightweight programming language.
JavaScript is programming code that can be inserted into HTML pages.
JavaScript inserted into HTML pages, can be executed
by all modern web browsers.
The <script> and </script> tells where the JavaScript starts and ends.
The lines between the <script> and </script> contain the JavaScript:
alert("My First JavaScript");
</script>
<!DOCTYPE html>
<!DOCTYPE html>
</html>
<!DOCTYPE html>
<h1>My Web Page</h1>
<p id="demo">A Paragraph</p>
<button type="button" onclick="myFunction()">Try it</button>
<script>
function myFunction()
{
document.getElementById("demo").innerHTML="My First JavaScript Function";
}
</script>
</body>
</html>
Use the "id" attribute to identify the HTML element:
<!DOCTYPE html>
The <script> Tag
To insert a JavaScript into an HTML page, use the <script> tag.The <script> and </script> tells where the JavaScript starts and ends.
The lines between the <script> and </script> contain the JavaScript:
syntax:
<script>alert("My First JavaScript");
</script>
JavaScript in <body>
Example:
<!DOCTYPE html>
<html>
<body>
.
.
<script>
document.write("<h1>This is a heading</h1>");
document.write("<p>This is a paragraph</p>");
</script>
.
.
</body>
</html>
A JavaScript Function in <head>
Example:
<!DOCTYPE html>
<html>
<head>
<script>
function myFunction()
{
document.getElementById("demo").innerHTML="My First JavaScript Function";
}
</script>
</head>
<script>
function myFunction()
{
document.getElementById("demo").innerHTML="My First JavaScript Function";
}
</script>
</head>
<body>
<h1>My Web Page</h1>
<p id="demo">A Paragraph</p>
<button type="button" onclick="myFunction()">Try
it</button>
</body></html>
A JavaScript Function in <body>
Example:
<!DOCTYPE html>
<html>
<body>
<h1>My Web Page</h1><p id="demo">A Paragraph</p>
<button type="button" onclick="myFunction()">Try it</button>
<script>
function myFunction()
{
document.getElementById("demo").innerHTML="My First JavaScript Function";
}
</script>
</body>
</html>
External JavaScripts
Scripts can also be placed in external files. External files often contain code to be used
by several different
web pages.
External JavaScript files have the file extension .js.
To use an external script, point to the .js file in the "src" attribute of the <script> tag:
Example:
<!DOCTYPE html>
<html>
<body>
<script src="myScript.js"></script>
</body>
</html>
<html>
<body>
<script src="myScript.js"></script>
</body>
</html>
Manipulating HTML Elements
To access an HTML element from JavaScript, you can use the document.getElementById(id) method.Use the "id" attribute to identify the HTML element:
Example
Access the HTML element with the specified id, and change its content:
<!DOCTYPE html>
<html>
<body>
<h1>My First Web Page</h1>
<p
id="demo">My
First Paragraph</p>
<script>
document.getElementById("demo").innerHTML="My
First JavaScript";
</script>
</body>
</html>
Writing to The Document Output:
The example below writes a <p> element directly into the HTML document output:
Example
<!DOCTYPE html>
<html>
<body>
<h1>My First Web Page</h1>
<script>
document.write("<p>My First JavaScript</p>");
</script>
</body>
</html>
<html>
<body>
<h1>My First Web Page</h1>
<script>
document.write("<p>My First JavaScript</p>");
</script>
</body>
</html>
download javascript tutorial in pdf format:
http://www.tutorialspoint.com/javascript/javascript_tutorial.pdf
www.ohio.edu/technology/.../java-script-reference-guide.pdf
learn javascript websites:
www.w3schools.com/js/default.asp
www.js-examples.com/
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