2.1.96 [W3C-HTML51] Section 6.3.2 Accessing other browsing contexts

V0251: The length attribute does not return the number of child browsing contexts of the active document

The specification states:

 ... Accessing other browsing contexts
     ...
     The length IDL attribute['s getter] ... must return the number of child browsing 
     contexts ...

EdgeHTML Mode

The length attribute does not return the number of child browsing contexts of the active document.