Google-maps – Google Maps API V3 : How show the direction from a point A to point B (Blue line)

Simply do the following:

I. Declare a global variable:

var markersArray = [];

II. Define a function:

function clearOverlays() {
  for (var i = 0; i < markersArray.length; i++ ) {
    markersArray[i].setMap(null);
  }
  markersArray.length = 0;
}

OR

google.maps.Map.prototype.clearOverlays = function() {
  for (var i = 0; i < markersArray.length; i++ ) {
    markersArray[i].setMap(null);
  }
  markersArray.length = 0;
}

III. Push markers in the 'markerArray' before calling the following:

markersArray.push(marker);
google.maps.event.addListener(marker,"click",function(){});

IV. Call the clearOverlays(); or map.clearOverlays(); function wherever required.

That's it!!

The best way is to use q parameter so that it displays the map with the point marked. eg.:

https://maps.google.com/?q=<lat>,<lng>