really inefficient regex in twitch.tv's embedded chat

twitchRegex.js

// The amount of time it takes for the RegEx to finish depends on the url of the current page:
var short = 'http://iridethelines.forumotion.com/post?p=183422&mode=editpost'
var medium = 'http://iridethelines.forumotion.com/t11564-threads-with-2-pages-freezing-tab#183414'
var reallyLong = 'http://iridethelines.forumotion.com/t10491p150-the-bofficial-b-chuggers-preview-thread-for-men'

var m = new RegExp("^https?://([a-zA-Z0-9]+.)*twitch.tv(:[0-9]+)?/.*$")
var t

t = Date.now(); m.test(short); console.log((Date.now() - t) / 1000)
t = Date.now(); m.test(medium); console.log((Date.now() - t) / 1000)
t = Date.now(); m.test(reallyLong); console.log((Date.now() - t) / 1000)