I am just looking for some general guidance here, I am happy to investigate the actual "how to" aspect myself, but I can't think of the general method that might be used.
I am setting up a site that is open to registered users to post on. I have added an addon that allows them to add info via a text field, but I want to be able to check that they have not added any code, html, hyperlinks etc into the text field (to minimise links, injecting code and so on).
What are some approaches that might be used to validate against that kind of thing? For example, I might validate that anything with word.word in it might be blocked because that indicates that there is a possible email address or website address. All suggestions and thoughts will be greatly appreciated.