Eclipse - PDT, prevent validation on some files

Hello there, sorry to bugging the list and I hope finding the answer quickly. Today I watch a youtube video which showing eclipse pdt and I want to try. It was amazing, it was so advanced after kate and if I handle one thing, I would be very happy. This thing checks every file in the project and validates it. So ? Eclipse found some veird errors (they use custom html element attirbuties or someting like that) and I can't find the way to fix it. Also it wasn't my code. My Question is Is there any way to prevent validation some files and directories under eclipse. Thanks Sancar