Functions are very important and useful in any programming language as they make the code reusable A function is a block of code which will be executed only if it is called. If you have a few lines of code that needs to be used several times, you can create a function including the repeating lines of code and then call the function wherever you want.
In this tutorial, you will learn-
How to Create a Function in JavaScript
Function with Arguments
JavaScript Return Value
Use the keyword function followed by the name of the function.
After the function name, open and close parentheses.
After parenthesis, open and close curly braces.
Within curly braces, write your lines of code.
Syntax:
function functionname()
{
lines of code to be executed
}
Input
Output
<html>
<head>
<title>Functions!!!</title>
<script type="text/javascript">
function myFunction()
{
document.write("This is a simple function.<br />");
}
myFunction();
</script>
</head>
<body>
</body>
</html>
You can create functions with arguments as well. Arguments should be specified within parenthesis
Syntax:
function functionname(arg1, arg2)
{
lines of code to be executed
}