I fed it a favorite regex... Bravo. Unfortunately, the permalinking fails with this particular regex, or I'd include it here. The visualization is so large, it more than fills my large screen. Still, pretty cool to see it render instantaneously and to watch it match example text. The regex is described here: http://www.cs.sfu.ca/~cameron/REX.html It will match either text or XML markup (it's used to tokenize XML), so try example text like '<div id="123">abc' or 'abc<?xml target?>'.

The JavaScript form of the regex follows: [^<]+|<(!(--([^-]-([^-][^-]-)->?)?|\[CDATA\[([^]]]([^]]+])]+([^]>][^]]]([^]]+])]+)>)?|DOCTYPE([ \n\t\r]+([A-Za-z_:]|[^\x00-\x7F])([A-Za-z0-9_:.-]|[^\x00-\x7F])([ \n\t\r]+(([A-Za-z_:]|[^\x00-\x7F])([A-Za-z0-9_:.-]|[^\x00-\x7F])|"[^"]"|'[^']'))([ \n\t\r]+)?(\[(<(!(--[^-]-([^-][^-]-)->|[^-]([^]"'><]+|"[^"]"|'[^']')>)|\?([A-Za-z_:]|[^\x00-\x7F])([A-Za-z0-9_:.-]|[^\x00-\x7F])(\?>|[\n\r\t ][^?]\?+([^>?][^?]\?+)>))|%([A-Za-z_:]|[^\x00-\x7F])([A-Za-z0-9_:.-]|[^\x00-\x7F]);|[ \n\t\r]+)]([ \n\t\r]+)?)?>?)?)?|\?(([A-Za-z_:]|[^\x00-\x7F])([A-Za-z0-9_:.-]|[^\x00-\x7F])(\?>|[\n\r\t ][^?]\?+([^>?][^?]\?+)>)?)?|/(([A-Za-z_:]|[^\x00-\x7F])([A-Za-z0-9_:.-]|[^\x00-\x7F])([ \n\t\r]+)?>?)?|(([A-Za-z_:]|[^\x00-\x7F])([A-Za-z0-9_:.-]|[^\x00-\x7F])([ \n\t\r]+([A-Za-z_:]|[^\x00-\x7F])([A-Za-z0-9_:.-]|[^\x00-\x7F])([ \n\t\r]+)?=([ \n\t\r]+)?("[^<"]"|'[^<']'))*([ \n\t\r]+)?/?>?)?)