Most people are able to read and understand text, even if it is all gibberish. The first and last letter need to stay the same as the correct spelling. The letters in between can be ordered any way and it remains readable.
Most poplee are able to read and userdatnnd txet, even if it is all gibsierbh. The fisrt and lsat letetr need to stay the same as the ccorert sllpieng. The lrteets in bweeten can be ordered any way and it rameins rdlabeae.
Bookmark (or better drag and drop it on the bookmark toolbar) the following bookmarklet: gibberish
Now you can click on the bookmarklet and convert any page into gibberish.