comment on

what do you do to prevent XSS reliably?

Sanitize user input using a accept known good only approach (link to owasp.com). I find Embperl::Form::Validate very useful, although there are many others as well.
Flip HTML::Mason's default_escape_flags so that if someone enters:
```
<script>load_malicious_javascript_from_hacker_site;</script>
[download]
```
into a text field in your blog, it is displayed verbatim rather than turned into executable code.

The OWASP Guide to Building Secure Web Applications version 3 draft is out. Is is certainly an interesting read for those concerned about web application security.

--
When you earnestly believe you can compensate for a lack of skill by doubling your efforts, there's no end to what you can't do. [1]

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