A callback is a function that is passed as an argument to another function and is executed after its parent function has completed<html><head>
<title>callback function</title> <script language="javascript" type="text/javascript"> function fParent(callback) { alert("This is parent function"); alert("Now call the callback function"); callback(); } function fCallback1() { alert("This is callback function 1"); } function fCallback2() { alert("This is callback function 2"); } function test() { fParent(fCallback1); fParent(fCallback2); } </script> </head> <body> <button onClick=test()>click me</button> </body> </html>