Question

我已经查看了我在这里找到的每个答案，但无法解决这个问题。我很确定我没有错过任何明显的东西。

我正在尝试加载基于lat longs的地图标记。问题是当我尝试返回AJAX响应为responseXML时它始终为null，如果我使用responseText它工作正常，但显然下一步不起作用。

这是生成XML的PHP：

<?php
header('Content-type: text/xml');
?>    
<?xml version="1.0" encoding="ISO-8859-1"?>
<properties>
    <![CDATA[
<?php 
if ($body != null): 
        foreach ($body as $property): ?>
        <property>
            <lat><?php echo $property -> lat; ?></lat>
            <long><?php echo $property -> long; ?></long>
            <name><?php echo $property -> property_name; ?></name>
            </property>
<?php endforeach;
endif; ?>
    ]]>
</properties>

我可以在Fiddler中看到请求正常

GET   /letsgo/index.php/hotmaps/get_properties_ajax/22.270888501350186/22.288560098193066/114.13720860290528/114.19827713775635   HTTP / 1.1

实体内容类型：text / xml

虽然当我在fiddler的XML视图中查看它时，它似乎是空的，

这是原始回复

HTTP/1.1 200 OK
Date: Tue, 15 Jan 2013 11:04:27 GMT
Server: Apache/2.4.2 (Win32) PHP/5.4.4
X-Powered-By: PHP/5.4.4
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Content-Length: 310
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/xml



<?xml version="1.0" encoding="ISO-8859-1"?>
<properties>
    <![CDATA[
        <property>
            <lat>22.2776</lat>
            <long>114.173</long>
            <name>Kaxo Tower test</name>
            </property>
        <property>
            <lat>22.2803</lat>
            <long>114.16</long>
            <name>Kuno Tower</name>
            </property>
    ]]>
</properties>

以下是每次移动地图时调用的创建标记功能

// make the ajax request
function loadXMLDoc(downUrl){
    var xmlhttp;
    if (window.XMLHttpRequest) {
        // code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp=new XMLHttpRequest();
      }
    else {// code for IE6, IE5
      xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    xmlhttp.onreadystatechange=function() {
      if (xmlhttp.readyState==4 && xmlhttp.status==200)
        {

            //var propertiesXml = xmlhttp.responseText; // WORKS FINE!!
            var propertiesXml = xmlhttp.responseXML; // ALWAYS null
            //alert(propertiesXml);     
            var propertiesRows = propertiesXml.getElementsByTagName("property");

            for (var i = 0; i < propertiesRows.length; i++) {           
            var propertiesRow = propertiesRows[i];
            var xmlLat = propertiesRow.getElementsByTagName("lat")[0];
            var xmlLong = propertiesRow.getElementsByTagName("long")[0];
            var propertyLatLong = new google.maps.LatLng(parseFloat(xmlLat.firstChild.data),parseFloat(xmlLat.firstChild.data));            
            // create each marker
            createMarker(propertyLatLong);
            }   

        }
      }
    xmlhttp.open("GET", downUrl, false); // false or true? makes no difference
    xmlhttp.setRequestHeader("Content-type", "text/xml");
    xmlhttp.send(); 
}

这是我用getElementsByTagName提供null的错误，Chrome控制台说

未捕获TypeError：无法调用方法'getElementsByTagName'为null

这是在我的本地Apache上运行

有什么建议吗？

/ **更新 - 工作代码** /

<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
    <style type="text/css">
      html { height: 100% }
      body { height: 100%; margin: 0; padding: 0 }
      #map_canvas { height: 100% }
    </style>
    <script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?key=APIKEYHERE&sensor=false">
    </script>

    <script type="text/javascript">  

      // initialise map 
      function initialize() {

      // set starting latlong
      var myLatlng = new google.maps.LatLng(22.2776, 114.173); 

      // set initial map options        
      var mapOptions = {
        center: myLatlng,
        zoom: 13,
        mapTypeId: google.maps.MapTypeId.ROADMAP
        };

      // create the map                       
      var map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions); 

      // listen for changes in map bounds - after map has stopped moving!!      
      google.maps.event.addListener(map,'idle', function () {      
        loadByBounds(map);          
        });                 
      }

      // if the bounds have changed 
      function loadByBounds(map) {  

        var bounds = map.getBounds();       
        var swPoint = bounds.getSouthWest();
        var nePoint = bounds.getNorthEast();

        // specific co ordinates
        var swLat = swPoint.lat();
        var swLng = swPoint.lng();
        var neLat = nePoint.lat();
        var neLng = nePoint.lng();               

        var downUrl = "<?php echo site_url('hotmaps/get_properties_ajax'); ?>/"+swLat+"/"+neLat+"/"+swLng+"/"+neLng;

        // load the 
        loadXMLDoc(downUrl, map); 

        // clear icons outside of bounding box

        //....


        }

        // make the ajax request
        function loadXMLDoc(downUrl, map){
            var xmlhttp;
            if (window.XMLHttpRequest) {
                // code for IE7+, Firefox, Chrome, Opera, Safari
                xmlhttp=new XMLHttpRequest();
              }
            else {// code for IE6, IE5
              xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
              }
            xmlhttp.onreadystatechange=function() {
              if (xmlhttp.readyState==4 && xmlhttp.status==200)
                {

                    var propertiesXml = xmlhttp.responseText; // WORKS FINE!!

                    // remove whitespaces from start and end (.trim() doesnt work)
                    propertiesXml = propertiesXml.replace(/^\s+|\s+$/g,'');                 

                    // manually parse to XML DOM object 
                    var parser = new DOMParser();                   
                    var xmlDoc;                 
                       try {
                            xmlDoc = parser.parseFromString (propertiesXml, "text/xml");
                        } catch (e) {
                            alert ("XML parsing error.");
                            return false;
                        };

                    //console.log(xmlDoc);

                    // get each property
                    var propertiesRows = xmlDoc.getElementsByTagName("property");   

                    //alert(console.log(propertiesRows));   
                    for (var i = 0; i < propertiesRows.length; i++) {

                        var propertiesRow = propertiesRows[i];
                        var xmlLat = propertiesRow.getElementsByTagName("lat")[0];
                        var xmlLong = propertiesRow.getElementsByTagName("long")[0];
                        var propertyLatLong = new google.maps.LatLng(parseFloat(xmlLat.firstChild.data),parseFloat(xmlLong.firstChild.data));           
                        // create each marker
                        createMarker(propertyLatLong, map);
                    }
                 }
             }
            xmlhttp.open("GET", downUrl, false);
            xmlhttp.setRequestHeader("Content-type", "text/xml");
            xmlhttp.send(); 
        }   

        // create new markers
        function createMarker(propertyLatLong, map){             
            var dynamicMarker = new google.maps.Marker({

                map:map,
                draggable:false,
                position: propertyLatLong
            });
            debugger;           
        }       
    </script>
  </head>
  <body onload="initialize()">      
    <div id="map_canvas" style="width:100%; height:100%"></div>
  </body>
</html>

Answer 1

您可以尝试自己解析XML：

var parser = new DOMParser();
var xmlDoc = parser.parseFromString(xmlhttp.responseText, "application/xml");

喜欢这个。

Answer 2

您的代码位于CDATA部分，因此解析器会将其忽略为标记。

Answer 3

我想知道为什么你希望解析器几乎跳过你的整个http响应体，似乎没有必要，它不包含任何可能被误解的东西。它甚至是你想要解析的数据，你没有明显的理由隐藏在你的例子中。

在这里查看CDATA的一些解释：http://www.w3schools.com/xml/xml_cdata.asp

您可以尝试评论开头和结束CDATA语句，如下所述：http://de.selfhtml.org/html/xhtml/unterschiede.htm

他们还声明，XML解析器默认采用UTF-8编码，如果配置不正确则拒绝解析，建议不要通过响应头覆盖exspected类型。

我更喜欢避免在块语句中打开和关闭php块，就像你做的那样，但我不是最新的编码约定，所以我可能错了。

<?php

header('Content-type: text/xml');
header ('Cache-Control: no-cache');
header ('Cache-Control: no-store' , false);

$response ='<?xml version="1.0" encoding="UTF-8"?>
<properties>';

if ($body != null): 
    foreach ($body as $property):
        $response .='<property>
            <lat>'.$property->lat.'</lat>
            <long>'.$property->long'.</long>
            <name>'.$property->property_name.'</name>
        </property>';
    endforeach;
endif;

$response .='</properties>';

echo responseText;

?>

responseText有效，但responseXML始终为null

3 个答案: