Find a simple and nice helper function from CSS-Tricks and convert it into CoffeeScript.

getQueryVariable = (variable) ->
  query = window.location.search.substring(1)
  vars = query.split("&")
  i = 0

  while i < vars.length
    pair = vars[i].split("=")
    return pair[1]  if pair[0] is variable
    i++
  false

Done =)

Reference:

• CSS-Tricks – Get URL Variables
• Javascript – Get URL Query String | Eureka!