1.constructor
The constructor property is the prototype member of every object that has a prototype
arr.constructor == Array //true means that arr is an array
2.isArray
arr.isArray()
3.length
4.prototype
1.constructor
The constructor property is the prototype member of every object that has a prototype
arr.constructor == Array //true means that arr is an array
2.isArray
arr.isArray()
3.length
4.prototype