A JavaScript function is a block of code designed to perform a particular task.
A JavaScript function is executed when "something" invokes it (calls it).
JavaScript Function Syntax
A JavaScript function is defined with the function keyword, followed by a name, followed by parentheses ().
Function names can contain letters, digits, underscores, and dollar signs (same rules as variables).
The parentheses may include parameter names separated by commas:
(parameter1, parameter2, ...)
The code to be executed, by the function, is placed inside curly brackets: {}
function name(parameter1, parameter2, parameter3) {
code to be executed
}
Function parameters are the names listed in the function definition.
Function arguments are the real values received by the function when it is invoked.
Inside the function, the arguments behave as local variables.
<!DOCTYPE html>
<html>
<body>
<p>This example calls a function which performs a calculation, and returns the result:</p>
<p id="demo"></p>
<script>
function myFunction(a, b) {
return a * b;
}
document.getElementById("demo").innerHTML = myFunction(4, 3);
</script>
</body>
</html>
Javascript Functions
Block Of Code To Perform A Particular Task
