Great! It's very simple and useful. One little thing, the regular expression input is in an html form, so if you hit enter (in most browsers) it POSTs to a bl

Great! It's very simple and useful. One little thing, the regular expression input is in an html form, so if you hit enter (in most browsers) it POSTs to a blank page and you can lose your work. You can make the form onsubmit="return false;" if you never want it to submit.