小编Mar*_*k H的帖子

我在Web Inspector中收到错误,如下所示:

TypeError: 'null' is not an object (evaluating 'myButton.onclick = function() {
var userName = myTextfield.value;
greetUser(userName);

return false;

}')

这是我的代码(HTML):

<h2>Hello World!</h2>
<p id="myParagraph">This is an example website</p>

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

<form>
  <input type="text" id="myTextfield" placeholder="Type your name" />
  <input type="submit" id="myButton" value="Go" />
</form>

这是JS:

var myButton = document.getElementById("myButton");
var myTextfield = document.getElementById("myTextfield");

function greetUser(userName) {
var greeting = "Hello " + userName + "!";
document.getElementsByTagName ("h2")[0].innerHTML = greeting;
}

myButton.onclick = function() {
var userName = …

大家好，我有以下代码：

  var map;
  var infowindow;


  function getLocation()
    {
    if (navigator.geolocation)
      {
      navigator.geolocation.getCurrentPosition(initialize);
      }
    else{x.innerHTML="Geolocation is not supported by this browser.";}
    }

  function initialize(position) {
    var pyrmont = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);

    map = new google.maps.Map(document.getElementById('map'), {
      mapTypeId: google.maps.MapTypeId.ROADMAP,
      center: pyrmont,
      zoom: 15
    });

    var request = {
      location: pyrmont,
      radius: 500,
      types: ['restaurant']
    };
 ...

基本上，如果我设置 Long/Lat 坐标，我可以让地图工作得很好，但我希望通过获取用户位置来传递这些坐标。使用上面的代码，地图显示在我的手机上，但出现以下错误：

TypeError: 'undefined' is not an object (evaluating 'position.coords.latitude')

但在桌面上我没有得到地图和以下错误：

   Uncaught TypeError: Cannot read property 'latitude' of undefined 

任何帮助都会很棒我是 Javascript 和这些 API 的新手