将结果集值传递给 JavaScript 函数

Pass resultset value to a javascript function

本文关键字：JavaScript 函数 值传 结果      更新时间：2023-09-26

我有一个结果集，如何将其值传递给javascript函数，并将内部指针移动到下一行。

<?php 
$q=mysql_query("select * from tbl_map")or die(mysql_error());
$i=0;
?>
<script>
$(document).ready(function() {
// Initialize the Google Maps API v3
var map = new google.maps.Map(document.getElementById('map'), {
  zoom: 15,
  mapTypeId: google.maps.MapTypeId.ROADMAP
});
var marker = null;
function autoUpdate() {
<?php 
mysql_data_seek($q,$i);
$row=mysql_fetch_assoc($q);
$i++;
?>
lat=<?php echo $row['latitude']; ?>;
long=<?php echo $row['longitude']; ?>;
  navigator.geolocation.getCurrentPosition(function(position) {  
    var newPoint = new google.maps.LatLng(lat, 
                                          long);
    if (marker) {
      // Marker already created - Move it
      marker.setPosition(newPoint);
    }
    else {
      // Marker does not exist - Create it
      marker = new google.maps.Marker({
        position: newPoint,
        map: map
      });
    }
    // Center the map on the new position
    map.setCenter(newPoint);
  }); 
  // Call the autoUpdate() function every 5 seconds
  setTimeout(autoUpdate, 5000);
}
autoUpdate();
      });
</script>

我想从数据库中获取纬度和经度并传递给自动更新（）但我无法向前移动内部指针。如何解决？

试试这个：在这种方法中，latitude数组和longitude被分配给一个JavaScript变量，json以json数据的形式。

    <script>
       // ---- PHP Starts here which fetch data and is placed immediately after <script> tag open
       // ---- and store to a variable in json format.
       <?php
            $q = mysql_query("select * from tbl_map")or die(mysql_error());
            $response = array();
            for($i = 0; $i < mysql_num_rows($q) ; $i++ )
            {
                mysql_data_seek($q, $i);
                $row = mysql_fetch_assoc($q);
                array_push( $response, array(
                    'lat'=>$row['latitude'],
                    'long'=>$row['longitude']
                ));
                // ------ Here php assigns the array of data to `json`
                // ------ `var json` is under scope of javascript
                echo 'var json = ' . json_encode($response) . ';';
            }
       ?>
    // ---- PHP part ends here and javascript start
    // ---- Testing the `json` var
    console.log(json);
    console.log(json.length);

    $(document).ready(function() {
        // Initialize the Google Maps API v3
        var map = new google.maps.Map(document.getElementById('map'), {
            zoom: 15,
            mapTypeId: google.maps.MapTypeId.ROADMAP
        });
        var c = 0;
        var marker = null;
        function autoUpdate() {
                console.log(json[c].lat);
                console.log(json[c].long);
                navigator.geolocation.getCurrentPosition( function(position)
                {
                    var newPoint = new google.maps.LatLng( json[c].lat, json[c].long );
                    if (marker) {
                        // Marker already created - Move it
                        marker.setPosition(newPoint);
                    }
                    else {
                        // Marker does not exist - Create it
                        marker = new google.maps.Marker({
                            position: newPoint,
                            map: map
                        });
                    }
                    // Center the map on the new position
                    map.setCenter(newPoint);
                });
            if (c == (json.length - 1)) { c = 0; } else { c++; }
            // Call the autoUpdate() function every 5 seconds
            setTimeout(autoUpdate, 5000);
        }
        autoUpdate();
    });
    </script>
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