我想全局使用变量检查

Question

我想全局使用check变量。因为我想将此文件包含在另一个文件中，并希望对保存位置的变量应用条件。但我无法在全球范围内使用它。请帮助我

    <script language="javascript">
    var check= "initial";
    function fun() {

    function displayLocation(latitude, longitude) {
    var request = new XMLHttpRequest();

    var method = 'GET';
    var url = 'http://maps.googleapis.com/maps/api/geocode/json?latlng=' +   latitude + ',' + longitude + '&sensor=true';
    var async = true;

    request.open(method, url, async);
    request.onreadystatechange = function () {

        if (request.readyState == 4 && request.status == 200) {
            var data = JSON.parse(request.responseText);
            var address = data.results[1];
          check = address.formatted_address;
           alert(check);

        }
    };
    request.send();
};

var successCallback = function (position) {
    var x = position.coords.latitude;
    var y = position.coords.longitude;
    displayLocation(x, y);
};

var errorCallback = function (error) {
    var errorMessage = 'Unknown error';
    switch (error.code) {
        case 1:
            errorMessage = 'Permission denied';
            break;
        case 2:
            errorMessage = 'Position unavailable';
            break;
        case 3:
            errorMessage = 'Timeout';
            break;
    }
    alert(errorMessage);
};

var options = {
    enableHighAccuracy: true,
    timeout: 1000,
    maximumAge: 0
};

   navigator.geolocation.getCurrentPosition(successCallback, errorCallback,      options);
   }
   fun();
   document.write(check);
  </script>