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Editorial Team
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Asked: 2026-06-04T14:47:05+00:00

function test() { alert(Array.join.call(arguments,’/’)) //alerts / alert(Array.prototype.join.call(arguments,’/’)) //alerts Js/JScript alert(Array.join(arguments,’/’)) //alerts Js/JScript } test(‘Js’,’JScript’);

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function test()
{
alert(Array.join.call(arguments,'/')) //alerts /
alert(Array.prototype.join.call(arguments,'/')) //alerts Js/JScript
alert(Array.join(arguments,'/')) //alerts Js/JScript
}
test('Js','JScript');

Why is this difference? Why is it needed to reference prototype first ?
Also why does just Array.join gives required result even when join expects just a separator argument.

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1 Answer

  1. Editorial Team

    Array.join is a global function. When using call, what you pass as a first argument is the this object inside the body of the join function, then the arguments for the join function.

    js> Array.join.call(null, [1, 2], "/")   
"1/2"

    Array.prototype.join is for instances of Array. Therefore, it expects this to be the actual array, which is why your second example works. Your second example amounts to calling Array.prototype.join with the this object being arguments, which is exactly arguments.join("/"). See MDN for an explanation.

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