what is the function in JavaScript?
JavaScript functions are blocks of code designed to perform specific tasks or operations.Javascript functions execute a block of code when it is called.
types of functions
1. predefined functions:
a. these types of functions are already created in JavaScript.
b. Predefined functions in JavaScript are like ready-made tools
c. example:
alert()
confrim()
prompt()
parseInt()
2. user-defined functions
a. user-defined functions are defined by you, the programmer.
b. You define user-defined functions using the function keyword.
c. syntax:
function functionName(parameter1, parameter2, ...) {
// Function body: code to be executed
}
ways to create functions:
1. function without argument without return
// Define a function named "show"
function show()
{
alert("hello javacsript");
}
// Call the function
show();
2. function with the argument without return
// Define a function named "show with a parameter name"
function show(name)
{
alert("hello" , name );
}
// Call the function with an argument "sagar"
show("sagar");
3. function with an argument with return
// Define a function named "show with parameters x and y"
function addition(x,y)
{
return x+y;
}
// Call the function with arguments 3 and 5
var added_val = addition(3,5);
alert(added_val);
note:
parameters: these are the variables passed in the function definition.
arguments: these are the values passed when the function is called.
Calling a function on a specific event
code:
<html>
<head>
</head>
<body>
<button onclick="welcome();">click to see message</button>
<script>
function welcome()
{
alert("welcome to");
confirm("my");
prompt("my website");
}
</script>
</body>
</html>
explanation:
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