Question

What is the event

 $(document).ready(function(){
   $("a").click(function(event){
     alert("Thanks for visiting!");
   });
 });

and also this one

 $(document).ready(function(){
   $("a").click(function(){
     alert("Thanks for visiting!");
   });
 });

these two JS blocks are doing the same thing, but one with an event, if someone could explain what is function(event), also I saw something like function(e),function(g), what are those? Is there a tutorial I could learn?

Answer 1

The callback function that you’re providing to $("a").click is a function that takes an argument. This argument is an event object containing details about the object. Your function declaration can take this argument with any name you like — event, e, g… and it can also simply leave it out since you’re not using it inside of your function.

Consider that these two functions are essentially the same:

function foo(hi) {
   alert(hi);
}

function foo(bye) {
   alert(bye);
}

And that you may leave out the argument if it’s not used:

function bar() {
   alert("hello!");
}

bar(12345);