/*
A callback function is a function passed into another function
as an argument, which is then invoked inside the outer function
to complete some kind of routine or action.
*/
function greeting(name) {
alert('Hello ' + name);
}
function processUserInput(callback) {
var name = prompt('Please enter your name.');
callback(name);
}
processUserInput(greeting);
// The above example is a synchronous callback, as it is executed immediately.
// What is callback functions in js
// Lets make a function
// Putting parameter in it "callback"
function func1(callback) {
console.log(callback); // Log 'callback'; And now our parameter callback is a function and we can call it from our func1 and this is what callback is
hello();
}
// Making one more function to print hello world in console
function hello() {
console.log("Hello world");
}
func1(hello); // Call func and give hello function as a arguement; Yes we can give function as arguement
// func1(hello()); // This is wrong way to give function as arguement
function greeting(name) {
alert('Hello ' + name);
}
function processUserInput(callback) {
var name = prompt('Please enter your name.');
callback(name);
}
processUserInput(greeting);
//Callback functions - are functions that are called AFTER something happened
const foo = (number, callbackFunction) => {
//first
console.log(number)
//second - runs AFTER console.log() happened
callbackFunction()
}
function greeting(name) {
alert('Hello ' + name);
}
function processUserInput(callback , {
var name = prompt('Please enter your name.');
callback(name);
}}
processUserInput(greeting);
function startWith(message, callback){
console.log("Clearly written messages is: " + message);
//check if the callback variable is a function..
if(typeof callback == "function"){
callback(); //execute function if function is truly a function.
}
}
//finally execute function at the end
startWith("This Messsage", function mySpecialCallback(){
console.log("Message from callback function");
})
function sum(num1,num2,callback){
let total = num1 + num2
callback(total)
}
sum(10,20,function(total){
// received total here
console.log(total);
})
sum(5,16,(total)=>{
console.log(total);
})
function greeting(name) {
alert(`Hello, ${name}`);
}
function processUserInput(callback) {
const name = prompt("Please enter your name.");
callback(name);
}
processUserInput(greeting);
<html>
<head>
</head>
<body>
<h1>Hello User</h1>
<h2> This is the softhunt.net</h2>
<script>
function showData(name, amt) {
alert(' Hello ' + name + '
Your entered amount is ' + amt);
}
function getData(callback) {
var name = prompt(" Welcome to the softhunt.net
What is your name?");
var amt = prompt(" Enter some amount...");
callback(name, amt);
}
getData(showData);
</script>
</body>
</html>