Need help to retrive data from MYSQL based on dropdown selection in wordpress

I am displaying a list of country in the drop down list, retrive it from the database . and i need to display price for the selected country based on the options chosen by the customers in the drop down list without that page getting refreshed.

the url i m passing in ajax is not calling the php file url: "cities.php",

is any one help me how to do that any suggestions.

i am use exec php plugin to write the php code in the page.

This is my code

                         <?php
 // Establish a database connection (adjust address, username, and password)

$con= mysqli_connect("localhost", "root", "") or die("Could not connect: " . mysql_error());

mysql_select_db("geo_ip");

// Create a query string

$query = "SELECT countryFROM  geo_ip ";

    $result=mysql_query($query) or die ("Unable to Make the Query:" . mysql_error() );
   echo "<select name=myselect onChange='get_cities(this.value)'>";  

       while($row=mysql_fetch_array($result)){ 

           echo "<OPTION VALUE=".$row['country'].">".$row['country']."</OPTION>";
        }

          echo "</select>"; 

        echo "<select name='city' id='city'></select>"; //We have given id to this dropdown

           ?>
          <script>
          function get_cities(country)
        {
         $.ajax({
       type: "POST",
       url: "cities.php", /* The country id will be sent to this file */
       beforeSend: function () {
       $("#price").html("<option>Loading ...</option>");
    },
   data: "country="+country,
   success: function(msg){
     $("#price").html(msg);
   }
   });
    } 
   </script>