ColdFusion's comment tags can be nested.

This isn't documented in Allaire's CFDOCS,

in fact the only reference to CF comments

I could find is in

Chapter 4 Quick Start to ColdFusion - Creating Simple Dynamic Pages --

Note the use of the comment convention used in ColdFusion pages:

<!--- and --->. ColdFusion comments use a form similar to HTML

comments, but with an additional hyphen.

Well, this isn't exactly true unless

you interpret the word "similar" loosely.

Unlike CF comments,

HTML comments are cannot be nested.

For example, consider the following block of HTML

this is uncommented HTML

<!-- this is a comment -->

this again is uncommented

<!-- this is another comment -->

finally, this too is uncommented

If you have ever tried to comment out an entire

block of HTML like the above, you will

have quickly discovered that

you can not just slap opening

and closing comment tags around the

block --

<!-- open my comment

this is uncommented

<!-- this is a comment -->

this again is uncommented

<!-- this is another comment -->

finally, this too is uncommented

close my comment -->

The above will not

give the intended results, because the opening <!-- tag

will be matched by the first --> tag encountered, despite the

fact that there was a nested <!-- between them.

Cold Fusion comments, however, can be nested, and the

following will

give the intended results --

<!--- open my CF comment

this is uncommented

<!--- this is a CF comment --->

this again is uncommented

<!--- this is another CF comment --->

finally, this too is uncommented

close my CF comment --->

Everything between the

<!---

and

--->

is one large CF comment, and none of it will be passed to

the web server by Cold Fusion.

Neat, eh?