declare callback function javascript code example
Example 1: javascript callback
function greeting(name) {
alert('Hello ' + name);
}
function processUserInput(callback) {
var name = prompt('Please enter your name.');
callback(name);
}
processUserInput(greeting);
Example 2: create callback function javascript
function add(a, b, callback) {
if (callback && typeof(callback) === "function") {
callback(a + b);
}
}
add(5, 3, function(answer) {
console.log(answer);
});
Example 3: javascript callback function
const message = function() {
console.log("This message is shown after 3 seconds");
}
setTimeout(message, 3000);