How argument is being passed in the function(which itself is an argument) in JavaScript -

How argument is being passed in the function(which itself is an argument) in JavaScript -

i have basic question javascript. consider next code:

var numbers = [4,2,3,4,5,4,3,2,1]; var everyresult = numbers.every(function(item,index,array) { alert(arguments.length); homecoming (item > 1); });

now in above code passing anonymous function argument of "every" function. how anonymous function getting 3 arguments(item,index,array).

this isn't basic javascript question, library question, , how "happens" depends on implementation.

this here sample implementation of every in javascript:

function every(array, fn) { for(var = 0; < array.length; i++) { fn(array[i], i, array); } }

you phone call this:

every([1,2,3,4], function(item, index, array) { // stuff });

as can see, it's every function itself, calls fn (which function pass in), , decides arguments pass.

javascript function