Suppose you want to print a web page, but it contains some text or personal information that you don’t want to show. With a simple JavaScript command, you can edit it – or almost any content on any web page.

Here’s how you do it: In Safari’s address field, type javascript: document.body.contentEditable = true and press Return. (To make it really easy, you can embed that code in a bookmarklet: Enter the code in the address field, then drag its URL icon – or favicon – to your bookmarks toolbar.) Any page tweaks will be visible to you alone (until you refresh); they won’t affect what anyone else sees when they visit that page.