title: how to get Javascript variable value in C#
body: <p>I have two Lat/long tables, 1000 rows each table. I wanted to calculate the distance between two latitude/longitude using Google Map API and store distance in DB.
  The code is working fine but the catch is how to return calculated distance from javascript. I tried hidden fields to store the distance since I have written the below code in page load, but it's not working:</p>
  
  <pre><code>        SqlConnection sql_con = new SqlConnection("Database=myDB;Server=mySever;User Id=myID;password=PWD");
          SqlCommand sql_cmd = new SqlCommand("select Zip,Latitude,Longitude from ZipCodes", sql_con);
          SqlDataAdapter sql_adt = new SqlDataAdapter(sql_cmd);
          DataSet dsZip = new DataSet();
          sql_adt.Fill(dsZip);
  
          sql_cmd = new SqlCommand("select * from MyPlaceLatLong", sql_con);
          sql_adt = new SqlDataAdapter(sql_cmd);
          DataSet dsStore = new DataSet();
          sql_adt.Fill(dsStore);
  
          for (int zcnt = 0; zcnt &lt; dsZip.Tables[0].Rows.Count; zcnt++)
          {
              for (int i = 0; i &lt; dsStore.Tables[0].Rows.Count; i++)
              {
                  Page.ClientScript.RegisterClientScriptBlock(GetType(), "myScssript", "&lt;script&gt;" +
                   "var origin1 = new google.maps.LatLng("+dsZip.Tables[0].Rows[zcnt]["Latitude"].ToString()+","+ dsZip.Tables[0].Rows[zcnt]["Longitude"].ToString()+");" +
                   "var origin2 = new google.maps.LatLng(" + dsStore.Tables[0].Rows[i]["lat"].ToString() + "," + dsStore.Tables[0].Rows[i]["long"].ToString() + ");" +
                    //"var origin1 = new google.maps.LatLng(55.930385, -3.118425);" +
                    //"var origin2 = new google.maps.LatLng(51.483061, -0.004151);" +
                   "var service = new google.maps.DistanceMatrixService();" +
                   " alert('Made it to calculateDistances');" +
                   "service.getDistanceMatrix(" +
                   "{" +
                     "origins: [origin1]," +
                     "destinations: [origin2]," +
                     "travelMode: google.maps.TravelMode.DRIVING," +
                     "unitSystem: google.maps.UnitSystem.IMPERIAL," +
                     "avoidHighways: false," +
                     "avoidTolls: false" +
                   "}, callback);" +
                   "function callback(response, status)" +
                     "{" +
                      "if (status == google.maps.DistanceMatrixStatus.OK) { " +
                      "var origins = response.originAddresses;   " +
                      "var destinations = response.destinationAddresses;" +
                      "for (var i = 0; i &lt; origins.length; i++) {" +
                      "var results = response.rows[i].elements;" +
                      "for (var j = 0; j &lt; results.length; j++) {" +
                      "var element = results[j];" +
                      "var distance = element.distance.text;" +
                      "var duration = element.duration.text; " +
                      "var from = origins[i];" +
                      "var to = destinations[j];" +
                     "alert('The distance:'+ distance);" +
                      "}}}}" +
                 "&lt;/script&gt;");
  
  
  
              }
          }
  </code></pre>