Google Maps Api V3 - Marker Disappears After Setposition

I'm having a problem with the maps markers. The map and marker load fine on the inital pageload. But when I try to update the marker location it simply disappears. The Alert window

Solution 1:

function(data) {
   alert(data);
   position = new google.maps.LatLng(data);
   ..

Looks very wrong; data is a string, probably containing "lat, lng", which google.maps.LatLng cannot be initialized with. new google.maps.LatLng requires a pair of type number in the arguments, like (number, number).

Do this instead :

data = data.split(',');position = new google.maps.LatLng(parseFloat(data[0]), parseFloat(data[1]));