Jan Östlund on Twitter: "Edit any text with Chrome Dev Tools. Sketch or check if you menu breaks with longer text. document.designMode = 'on'

There’s a neat setting hidden in most modern browsers: document.designMode='on'; which will give you the power of a text editor on a currently opened website. It means you can edit any text on the page live, and, with that, test your design against variable (user) content.