Javascript counting number of objects in object

Question

I have an object something like:

Object {0=Object, 1=Object, 2=Object} // Output from console.log(obj.Data);

But there is no method for me to count the number of objects in the object and then extract the attribute value from the subobjects.

I attempted

console.log(obj.Data[0].length); // It does not work

console.log(obj.Data.length); // It does not work

This is a little difficult for me. I'm hoping you can assist.