Question

我试过这段代码：

<!DOCTYPE html>
<html>
  <head>
    <title>Location Location Location</title>

    <script type="text/javascript" charset="utf-8">

    var watchID = null;

    // PhoneGap is ready
    //
    function f() {
        // Update every 1 ms seconds
        var options = {enableHighAccuracy: true,timeout: 5000,maximumAge: 0,desiredAccuracy: 0, frequency: 1 };
        watchID = navigator.geolocation.watchPosition(onSuccess, onError, options);
    }

    // onSuccess Geolocation
    //
    function onSuccess(position) {
        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");
        }       
        var str = 'Latitude: '  + position.coords.latitude      + '<br>' +
                  'Longitude: ' + position.coords.longitude     + '<br>' +
                  'Timestamp: ' + position.timestamp     + '<br>' ;
        var url = "load.php";
        var params = "data="+str;
        xmlhttp.open("GET", url+"?"+params, true);
        document.body.innerHTML += str;
        document.writeln("line 33");
        xmlhttp.send();
        //document.writeln("send");
        //document.writeln(str);
    }

    // clear the watch that was started earlier
    // 
    function clearWatch() {
        if (watchID != null) {
            navigator.geolocation.clearWatch(watchID);
            watchID = null;
        }
    }

    // onError Callback receives a PositionError object
    //
    function onError(error) {
      alert('code: '    + error.code    + '\n' +
            'message: ' + error.message + '\n');
    }

    </script>
  </head>
  <body>
    <p id="geolocation">Watching geolocation...</p>
    <button onclick="f();"> Watch</button>     
  </body>
</html>

你可以看到我添加

var options = {......, frequency: 1 };
watchID = navigator.geolocation.watchPosition(onSuccess, onError, options);

但是，如果我进入制表符并退出并输入agin，我将获得新的结果。

我该怎么办？

Answer 1

规范未提及频率选项，表明此参数被忽略。 W3C Geolocation spec

Answer 2

您的代码似乎工作正常：http://jsfiddle.net/Mgk9J/1/

我在Android上进行了测试，当我移动手机时，新线路出现了。然而，在Chrome桌面中，当我更改标签时它会绘制新行，即使它们与最后一个标签相同，根据规范，这不是正确的行为。

桌面版本无论如何都没有绘制新行，计算机没有移动所以有一点意义，因此不应该触发新成功的calbacks执行。

<html><head>
  <meta http-equiv="content-type" content="text/html; charset=UTF-8">
  <title> - jsFiddle demo</title>

  <script type="text/javascript" src="/js/lib/dummy.js"></script>




  <link rel="stylesheet" type="text/css" href="/css/result-light.css">

  <style type="text/css">

  </style>



<script type="text/javascript">//<![CDATA[ 
window.onload=function(){
    var watchID = null;

    // PhoneGap is ready
    //
    function f() {
        // Update every 1 ms seconds
        var options = {enableHighAccuracy: true,timeout: 5000,maximumAge: 0,desiredAccuracy: 0, frequency: 1 };
        watchID = navigator.geolocation.watchPosition(onSuccess, onError, options);
    }

    // onSuccess Geolocation
    //
    function onSuccess(position) {

        var str = 'Latitude: '  + position.coords.latitude      + '<br>' +
                  'Longitude: ' + position.coords.longitude     + '<br>' +
                  'Timestamp: ' + position.timestamp     + '<br>\r\n' ;
        document.getElementById('result').value += str;
    }

    // clear the watch that was started earlier
    // 
    function clearWatch() {
        if (watchID != null) {
            navigator.geolocation.clearWatch(watchID);
            watchID = null;
        }
    }

    // onError Callback receives a PositionError object
    //
    function onError(error) {
      alert('code: '    + error.code    + '\n' +
            'message: ' + error.message + '\n');
    }

    document.getElementById('button').addEventListener('click', f);
}//]]>  

</script>


</head>
<body>
      <p id="geolocation">Watching geolocation...</p>
    <button id="button"> Watch</button>
    <textarea id="result" cols="100" rows="10"></textarea>






</body></html>

navigator.geolocation.watchPosition - 频率

2 个答案: