title: Why is a JavaScript Array index at most 4294967294 but not 4294967295?
body: <p>JavaScript's index is 32 bit, so it seems that the array index should be able to go up to 4294967295 for a total of 4294967296 elements.  But in fact the highest index is 4294967294.  Since an array has a <code>length</code> property, I don't see a reason for having a null as the last element.  Is there a reason the maximum index is 4294967294 but not 4294967295?</p>