tElementById('contentEditableTrue');
        assert_equals(getComputedStyle(contentEditableTrue).getPropertyValue('user-modify'), '');
    }, 'contenteditable="true" doesn\'t use unsupported user-modify property');

    test(function() {
        const contentEditablePlainText = document.getElementById('contentEditablePlainText');
        assert_equals(getComputedStyle(contentEditablePlainText).getPropertyValue('user-modify'), '');
    }, 'contenteditable="plaintext-only" doesn\'t use unsupported user-modify