These new global attributes are additions in Microsoft Internet
Explorer 5.5. They help allow IE to become not just a static web page
viewing device, but a platform that can dynamically edit web pages as well.
Specifies whether or not the contents of the element may be modified by the user.
Values: True - The content may be edited by the user. False - The content may not be edited by the user. Inherit - The control over the ability to edit an
element is inherited from its parent element.
This attribute controls whether an element gives visual feedback
when it has control 'focus'. In Windows this is indicated by a dotted
rectangle within the elements' rendering box. This attribute does not
specify how focus is given to an element, only whether visual feedback
for that state is visible.
(IE's reference says that this attribute takes "true" and "false"
values, but in direct testing, they both seem to have the same effect.
Using this attribute as a standalone (no value) hides the element focus
visual feedback, and not using this attribute defaults to having the
element focus state giving visual feedback.)
This attribute indicates the user selectability for an element (usually
initiated with a pointing device.) Element content that has this attribute
set to "on" can still be selected by selecting surrounding content.
Conversely, setting the UNSELECTABLE attribute to "off" also does not
ensure that the element is selectable either.
Values: On - Selection by the user is prohibited. Off - Selection by the user is allowed.
For some reason, IE5.5 doesn't support the HIDEFOCUS attribute on the
CODE and NOBR elements. There doesn't appear to be anything special
about these elements (indeed, there are many elements very much like
these in the same class that DO support the HIDEFOCUS
attribute that it seems these small omissions seem glaring by comparison.)
Microsoft's documentation says that INPUT TYPE=radio is supported with
the CONTENTEDITABLE attribute, but not INPUT TYPE=checkbox. These two
elements seem like an equivalence situation, so I included INPUT TYPE=checkbox
as being supported. It may or may not be.
It looks like the UNSELECTABLE="yes" value only means that selection can
not begin INSIDE the elements contents. If you start the selection outside
the element with this attribute set to "yes", you can then select whatever
you want inside the element. The only application of this attribute I can
think of off the top of my head for something like this is application
to a top-level element BODY.