Can you default a value of an attribute based on a value of an attribute in another work item

Question:  Can you default a value from an attribute from one work item into another work item that has the same field?

We don't want to have manually update the workitem with the same information that is included in another work item. 

Example:  If I update attribute A with a value in workitem 1 and workitem 2 also contains attribute A, we want the value carried over that was put in attribute A in Workitem 1 to default into attribute A of workitem 2.

Can we do this with a javascript or will this require an extension?