var directionDisplay;
    var directionsService = new google.maps.DirectionsService();
    var map;

var start = new google.maps.LatLng(51.47482547819850,-0.37739553384529);
var myOptions = {
  zoom:7,
  mapTypeId: google.maps.MapTypeId.ROADMAP,
  center: start
}
map = new google.maps.Map(document.getElementById("map"), myOptions);

function renderDirections(result) {
    var directionsRenderer = new google.maps.DirectionsRenderer();
    directionsRenderer.setMap(map);
    directionsRenderer.setDirections(result);
  }

function requestDirections(start, end) {
  directionsService.route({
    origin: start,
    destination: end,
    travelMode: google.maps.DirectionsTravelMode.DRIVING
  }, function(result) {
    renderDirections(result);
  });
}

for(i=0;i<add.length;i++)
 {
  requestDirections(start_add[i], end_address[i]);
 }
 }