Interestingly, IE interprets the source code.

Recently noticed that stumbled upon such

var array = [1, 2, 3, ];


Internet Explorer creates an array object, in which there are actually 3 elements, but length == 4 (!).
Normal browsers behave differently - there are 3 elements and length == 3 . To some extent, both behaviors seem logical to me, what do you think?

You can check here .