querystring-lite.js

function parseQuerystring (key) {
  var href = location.href;
  var start = href.indexOf('?');
  var obj = href.slice(start+1).split('&');
  var ret = {};
  obj.forEach(function (item) {
    var vals = item.split('=');
    var key = vals[0];
    var val = decodeURI(vals[1]).replace(/\+/g, ' ');
    ret[key] = val;
  });

  if (!key)
    return ret;
  else
    return ret[key];
}