Why does jQuery have a callback function?

However, since JQuery effects require some time to finish, the following lines of code may get executed while the previous effects are still being executed. This is bound to create errors and overlapping of effects and animations. To prevent this from occurring JQuery provides a callback function for each effects.

What does callback() actually do?

what does callback () actually do? it does whatever you want it to do, you define it. if you pass alert as callback it will either alert true or false, for example. When you pass a function as an argument, it is known as a callback function, and when you return a value through this callback function, the value is a parameter of the passed function.

Is there a callback function in socket Io?

The callback is an argument of the callback function for the on () function, so it's declared in what ever software you're using, I'm guessing socket.io, but I've never seen a callback like that in socket.io, are you sure there even is a callback function in whatever you're using ? Thanks for the reply.

Is a JavaScript callback still executed synchronously?

Generally, JavaScript allows function as a parameter. So any function that is passed as an argument is called a callback function. I think now callback is understandable to you. But isn't it still executed synchronously? So callback is basically passing function reference and it is still executed synchronously.