RegExp.escape = function(text) {
  if (!arguments.callee.sRE) {
    var specials ='/.*+?|()[]{}\\'.split('');
    arguments.callee.sRE = new RegExp('(\\' + specials.join('|\\') + ')','g');
  }
  return text.replace(arguments.callee.sRE, '\\$1');
}