A bookmarklet that masks all text and images on any page, using only CSS. It doesn't modify the page's DOM and works for every script (Latin, Chinese, Japanese, etc.). It's useful for screenshots, screen sharing, and demos.
Create a new bookmark in your browser, name it something like "Mask page", and paste the entire script below as the URL (it starts with javascript:). In Chrome, right-click the bookmarks bar, choose "Add page...", and paste the script into the URL field.
If the bookmark does nothing, check that the URL still starts with javascript:. Chrome sometimes drops it when pasting.