A very simple code to illustrate the difference.

var x = [0, 3, 1, 2];
console.debug('debug', x);
console.log('log', x);
// above display the same result
x.splice(1, 2);
// below display kind of a different result
console.debug('debug', x);
console.log('log', x);

The javascript value is exactly the same but console.log() displays it a bit differently than before applying splice() method. Because of this I lost quite a few hours as I thought splice is acting funny making my array multidimensional or something.

I just want to know why does this work like that. Does anyone know? :)