php - Automatically query MySQL and output results with AJAX -

i have problem display gps coords automatically on google map. when implement map static works fine, try dynamically. means when new gps coord saved database, map should refresh automatically.

i implemented in 1 .php file. show map coords user must select entry, link entry looks -> http://trackmyrun1.at/index.php?page=show_runs&data1=get&data2=1

    <?php     $result = mysql_query("select * fifa_gps run_id=".$_get['data2']."");       while ($line = mysql_fetch_array($result)) {     $cords[] = "new google.maps.latlng(" . $line['lat'] . ", " . $line['longt'] . "),";     }      $cord_start = explode("(", $cords[0]);     $cord_pos_start = explode(")", $cord_start[1]);      $cord_end = explode("(", $cords[count($cords)-1]);     $cord_pos_end = explode(")", $cord_end[1]);      echo $sys->overall_distance($_get['data2']);     ?>          <div id="map-canvas" style="height:400px"/>     <script type="text/javascript">     var seconds = 1;     var divid = "map-canvas";     var url = "http://localhost/alt/fifa-europaliga/index.php?page=show_runs&data1=get&data2=<?php echo $_get['data2']; ?>";              function refreshdiv(){              // xmlhttprequest object              var xmlhttp;             try{             xmlhttp=new xmlhttprequest(); // firefox, opera 8.0+, safari             }             catch (e){             try{             xmlhttp=new activexobject("msxml2.xmlhttp"); // internet explorer             }             catch (e){             try{             xmlhttp=new activexobject("microsoft.xmlhttp");             }             catch (e){             alert("your browser not support ajax.");             return false;             }             }             }              // timestamp preventing ie caching request              fetch_unix_timestamp = function()             {             return parseint(new date().gettime().tostring().substring(0, 10))             }              var timestamp = fetch_unix_timestamp();             var nocacheurl = url+"?t="+timestamp;              // code...              xmlhttp.onreadystatechange=function(){             if(xmlhttp.readystate==4){             document.getelementbyid(divid).innerhtml=xmlhttp.responsetext;             settimeout('refreshdiv()',seconds*1000);             }             }             xmlhttp.open("get",nocacheurl,true);             xmlhttp.send(null);             }              // start refreshing process              var seconds;             window.onload = function startrefresh(){             settimeout('refreshdiv()',seconds*1000);             }             <!--     refreshdiv();     // -->     </script>     <script type="text/javascript">     function initialize() {     var mylatlng = new google.maps.latlng(<?php echo $cord_pos_start[0]; ?>);     var mapoptions = {         zoom: 15,         center: mylatlng,         maptypeid: google.maps.maptypeid.roadmap     };      var map = new google.maps.map(document.getelementbyid("map-canvas"), mapoptions);      var flightplancoordinates = [         <?php echo implode('', $cords); ?>     ];      var image_start = 'http://labs.google.com/ridefinder/images/mm_20_green.png';      var marker = new google.maps.marker({         position: mylatlng,         map: map,         title:"start",         icon: image_start            });      var image_end = 'http://labs.google.com/ridefinder/images/mm_20_red.png';      var endmarker = new google.maps.marker({         position: new google.maps.latlng(<?php echo $cord_pos_end[0]; ?>),         map: map,         title:"ende",         icon: image_end          });      var flightpath = new google.maps.polyline({         path: flightplancoordinates,         strokecolor: "#ff0000",         strokeopacity: 0.5,         strokeweight: 5     });      flightpath.setmap(map);     }     initialize();     </script>   .... 

before first refresh see map , path on , after 1 refresh error:

warning: mysql_fetch_array() expects parameter 1 resource, boolean given in c:\xampp\htdocs\alt\fifa-europaliga\content\show_runs.php on line 4

notice: undefined variable: cords in c:\xampp\htdocs\alt\fifa-europaliga\content\show_runs.php on line 8

notice: undefined offset: 1 in c:\xampp\htdocs\alt\fifa-europaliga\content\show_runs.php on line 9

notice: undefined variable: cords in c:\xampp\htdocs\alt\fifa-europaliga\content\show_runs.php on line 11

can me?

before can run query, must connect server , select database.

$db = mysql_connect('hostname|ip', 'user', 'password'); mysql_select_db('database_name', $db); $result = mysql_query('select ...', $db); 

if query fails, mysql_query return false, explains error expecting resource , getting boolean.

the warning you're getting mysql_fetch_array needing resource means query failing. reasons may fail include:

1. not connected correct database
2. missing permissions on database
3. table doesn't exist, mistyped, etc
4. mistyped fields, query, etc. (bad query)

in cases, can check error printing out mysql_error().