Bug
var obj = Object.create({}.constructor.prototype);
//var obj = Object.create(Object.getPrototypeOf({}));
//var obj = {};
obj['0'] = null;
obj['1'] = null;
alert(obj.hasOwnProperty('0')); // IE9,10 - false
alert(obj.hasOwnProperty('1')); // IE9,10 - false
Fix
var obj = Object.create({}.constructor.prototype);
//var obj = Object.create(Object.getPrototypeOf({}));
//var obj = {};
obj['0'] = null;
obj['1'] = null;
obj['x'] = null; // fix
alert(obj.hasOwnProperty('0')); // true
alert(obj.hasOwnProperty('1')); // true