When parsing your input, hsc performs a syntax check on it. It
tests for things like missing end-tags, illegal tag nesting or missing
required tags.It also tests attributes for tags, e.g. allowed values
for the ALIGN option of <IMG>.
However, the syntax check of hsc is not very powerful compared to tools that only handle this task.
(Technical note: Most errors hsc handles are of the kind "Well, now a
have to program
this if (..) to avoid an enforcer hit/segmentation
fault, why not display an error message now..".)
So if hsc does not report any syntax errors, it doesn't mean that your source is 100% correct. For a more complete and strict test, take a look at tools mentioned at Related Stuff.