HTML spell checking compatibility

I am trying to write a crawler that goes through a rather large website and
produces a list of files with misspelt words.

The trouble is that some pages include the text

<style type="text/css">
<!--
a:link {
        text-decoration: none;
}
a:active {
        text-decoration: none;
}
-->
</style>

Or similar, which, when present, ends up with a whole lot of incorrect
errors after (for example td, tr tags are detected as errors)

When I run aspell in interactive mode, I don't get this error, however
running it using

aspell -a -H < filename

produces an error.  It seems to be dependent on the style tag, removing it
gets rid of the errors.

Am I doing something wrong?

Thanks