Get some parameters from the query string as an object.

query-params

/* Get querystring parameter's value */
function getParameterByName(name) {
  name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]");
  var regexS = "[\\?&]" + name + "=([^&#]*)";
  var regex = new RegExp(regexS);
  var results = regex.exec(window.location.search);
  if(results == null)
    return null;
  else
    return decodeURIComponent(results[1].replace(/\+/g, " "));
}

function getQueryParams(fields) {
  var data = {}, value = null;

  for (var i = 0; i < fields.length; i++) {
    value = getParameterByName(fields[i]);
    if (value) 
      data[fields[i]] = value;
  }
  return data;
}

fields = ['file', 'type', 'title'];
getQueryParams(fields)