Add or Modify url query string with javascript and JQuery

modify_query_string.js

// Not Required Jquery
// currentURL = location.protocol + '//' + location.host + location.pathname + location.search + location.hash

function ModifyQueryString(url, newKey, newValue){
    var params = {}
    var urlSplits   = url.split("?");
    var baseURL     = urlSplits[0]
    var queryString = urlSplits[1]

    if(!queryString) {
      params[newKey] = newValue

      var hashSplits = baseURL.split("#")
      baseURL  = hashSplits[0]
      var hash     = hashSplits[1]
      var result   = baseURL + "?" + SerializeParam(params)
      if(hash)
        result  += "#" + hash

      return result
    }

    var hashSplits  = queryString.split("#")
    queryString     = hashSplits[0]
    var hash        = hashSplits[1]

    if (queryString) {
        queries = queryString.split("&");
        for (var i=0; i<queries.length; i++){
          var keyValues = queries[i].split('=')
          params[keyValues[0]] = keyValues[1]
        }
    }
    params[newKey] = newValue

    // require jquery
    var result = baseURL + "?" + SerializeParam(params)
    if(hash)
      result += "#" + hash

    return result
}

function SerializeParam(params) {
  if(typeof $ !== "undefined" && typeof $.param !== "undefined" )
    return $.param(params)

  var queryString = ""
  for(prop in params) {
    queryString += prop + "&" + encodeURIComponent(params[prop])
  }
  return queryString
}


// spec for unit test.
/*
  # url without hash and query string
  var result = ModifyQueryString("http://www.bookmebus.com", "id", "order-123")
  expect(result).to eq "http://www.bookmebus.com?id=order-123"

  # url with hash and no query string
  var result = ModifyQueryString("http://www.bookmebus.com#popular", "id", "order-123")
  expect(result).to eq "http://www.bookmebus.com?id=order-123#popular"


  # url with query string no hash
  var result = ModifyQueryString("http://www.bookmebus.com?id=order-123&p=pipay", "p", "abapay")
  expect(result).to eq "http://www.bookmebus.com?id=order-123&p=abapay"

  # url with query string no hash
  var result = ModifyQueryString("http://www.bookmebus.com?id=order-123&p=pipay#payment-local", "p", "abapay")
  expect(result).to eq "http://www.bookmebus.com?id=order-123&p=abapay#payment-local"

*/