geolocation.getcurrentposition write to file?

agentv · 02-07-2013, 04:50 AM

Code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Save Location</title>
</head>
<body on onload="getLocation()">
<p id="demo"></p>
<body>
<script>
var x=document.getElementById("demo");
function getLocation()
  {
  if (navigator.geolocation)
    {
    navigator.geolocation.getCurrentPosition(showPosition);
    }
  else{x.innerHTML="Geolocation is not supported by this browser.";}
  }
function showPosition(position)
  {
  x.innerHTML="Latitude: " + position.coords.latitude + 
  "<br>Longitude: " + position.coords.longitude;	
  }
  function showError(error)
  {
  switch(error.code) 
    {
    case error.PERMISSION_DENIED:
      x.innerHTML="User denied the request for Geolocation."
      break;
    case error.POSITION_UNAVAILABLE:
      x.innerHTML="Location information is unavailable."
      break;
    case error.TIMEOUT:
      x.innerHTML="The request to get user location timed out."
      break;
    case error.UNKNOWN_ERROR:
      x.innerHTML="An unknown error occurred."
      break;
    }
  }
</script>
</body>
</html>

Hi. I'm pretty new to this stuff. I have figured out what I want JS to do, but I am not confident whether I can record this. For the demo, I am able to acquire user LONG/LAT and display it through x.innerHTML or alert. How would I go about recording and date stamping this to a file or a database? Would I need to toy around with php for this? Any help is greatly appreciated!

xelawho · 02-07-2013, 02:13 PM

yeah, you're pretty much down to php and ajax or something similar - javascript can't really write to files (well, if you're IE only and you just want to write a file to the user's machine and they give you permission to do so, you can but really from what it sounds like that isn't the case).

I made a google map that saves clicked locations to the database - you can see it here. That's kind of a different thing, but there is some overlap. I followed the tutorial here for setting up the php side, which I had no idea about and still only really vaguely understand how it works... but hey - the important thing is that it works, right?

xelawho · 02-07-2013, 02:44 PM

another thing is that, as your code allows for, sometimes geolocation fails. And sometimes it works, but is way off. I don't know how fancy you want to get, but you can build error handling into the callback from getposition and have a fallback (such as ip address lookup) and if you want to incorporate a map into your page, you can allow the user to drag the estimated position to their real location.

A couple of examples:

draggable location with a choice of tracking techniques

error handling - tries for geolocation, goes with IP lookup if that fails or user denies browser access to location

rnd me · 02-07-2013, 10:03 PM

you can easily download a string as a file in modern browsers. but what good does that do? you probably want to collect the data, and for multi-device input, a server side language like php or node.js is the only way to go.