HTML DOM Document implementation

Does this document has the feature DOM 1.0?

document.implementation.hasFeature("DOM", "1.0");

Does this document has the feature TESLA X?

document.implementation.hasFeature("TESLA", "X");

Description

The implementation property returns the DOMimplementation object that handles the document.

The DOM 1 Recommendation (1998) only specified one method for this object: hasFeature().

The hasFeature() method was ment to check if a DOM module was supported by the browser:

let answer = document.implementation.hasFeature("DOM", "1.0");

Problem is: All modern browsers always return true.

document.implementation

Type	Description
Object	A DocumentImplementation object. The document's implementation object.

document.implementation is a DOM Level 1 (1998) feature.

It is fully supported in all browsers:


Chrome	Edge	Firefox	Safari	Opera	IE
Yes	Yes	Yes	Yes	Yes	9-11