JavaScript Custom callback function sample code

If you call it directly in function A, then the callback function is limited to death. But using a function to do a parameter has the following benefits: when you (b) A function B becomes a callback function, and you can also be a (c) this time, function C becomes a callback function. If you write the Functiona () {...; b ();} It loses the flexibility of the variable.

The code is as follows:

function A (index,callback) {

Callback (index);

}

Function B (index) {

alert (index);

}

A (10000,B);