jQuery全局变量值超出功能[重复]

Question

var hhhhhhh = '';
        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 addressComponents = data.results[0].address_components;
                    for (i = 3; i < 4; i++) {
                        hhhhhhh = addressComponents[i].long_name;
                    }
                }
            };
            request.send();
        }
        console.log(hhhhhhh);

var hhhhhhh 没有从 displayLocation 函数中获取任何值。在控制台中，函数外部为 null，而函数内部获取其值。请帮忙。谢谢

Answer 1

你必须在 console.log 输出之前调用你的函数

var hhhhhhh = '';
function displayLocation(latitude, longitude) {
  //your code
   hhhhhhh = "Value";
}
displayLocation(0, 0);
console.log(hhhhhhh);

Answer 2

你需要调用函数然后控制台值：

var hhhhhhh = ''; 功能显示位置（纬度，经度）{ 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 addressComponents = data.results[0].address_components;
                    for (i = 3; i < 4; i++) {
                        hhhhhhh = addressComponents[i].long_name;
                    }
                }
            };
            request.send();
        }

   displayLocation(lat,long) //  you need to call the function and then console the value

        console.log(hhhhhhh);