getUrlParameter

getUrlParameter.js

var getUrlParameter = function getUrlParameter(sParam) {
  var sPageURL = decodeURIComponent(window.location.search.substring(1)),
    sURLVariables = sPageURL.split('&'),
    sParameterName,
    i;
  for (i = 0; i < sURLVariables.length; i++) {
    sParameterName = sURLVariables[i].split('=');

    if (sParameterName[0] === sParam) {
      return sParameterName[1] === undefined ? true : sParameterName[1];
    }
  }
};

if (getUrlParameter('f')) {
  var param = getUrlParameter('param');
}