Question

我正在努力从页面获取jsonp信息，我想在该信息上运行各种功能。信息很好，但我似乎无法找到一种方法使其在函数之外可访问。我知道它与闭包和功能范围有关，但我无法弄清楚如何使其工作，任何想法？

我可以通过多次调用json文件来实现我在脚本的其余部分中尝试做的事情，但我认为最好只查询json一次并将其弹出到变量中并尝试解决这个问题？我对这个设置比较新，所以任何建议都值得赞赏。

从下面的代码中，我希望能够在运行后获取getData方法之外的allMatches变量。

感谢您的时间，所有人都非常感谢。

var AppInfo = {
    getData :  function(){

                var responseJsonVar;
                var callbackName, script, newInfo, mydata,allMatches;
                // Get a random name for the callback
                callbackName = "checkGames" + new Date().getTime() + Math.floor(Math.random() * 10000);

                // create the jsonP script call on the page
                script = document.createElement('script');
                script.src = "http://www.hookhockey.com/index.php/temp-gillian/?callback=" + callbackName;
                document.documentElement.appendChild(script);

                // call the json
                window[callbackName] = function(data) {

                    responseJsonVar = data; // this is the info back from the json file

                    //the filtered data source from json
                    var allMatches = responseJsonVar["matches"];

                    console.dir('allMatches inside the function: ' + allMatches); //this comes back fine



                        // Remove our callback ('delete' with 'window properties fails on some versions of IE, so we fall back to setting the property to 'undefined' if that happens)
                        try {
                            delete window[callbackName];
                        }
                        catch (e) {
                            window[callbackName] = undefined;
                        }

         //I've tried putting a return value (return allMatches) in here and then calling window[callbackName]() outside of the function but I get undefined for matches

                }; // end  window[callbackName] function

    //this is what I think I should be doing to get the info out on its own
    console.dir('allMatches OUTSIDE the function: ' + allMatches); //this doesn't come back 'allMatches is not defined'


    } //end getdata method

} //end AppInfo


AppInfo.getData();

Answer 1

您可以在名为AppInfo的{{1}}对象上创建一个属性，并在数据从jsonp调用返回时设置该属性：

allMatches

请注意，我修改了第二个var AppInfo = { allMatches: null, // NEW PROPERTY TO HOLD RETURNED DATA confirmDataAvailableOutsideFunction: function () { // NEW FUNCTION TO VERIFY DATA AVAILABLE OUTSIDE getData() console.dir('AppInfo.allMatches OUTSIDE the function AFTER jsonp call executes: ' + AppInfo.allMatches); //this doesn't come back 'allMatches is not defined' }, getData: function () { var responseJsonVar; var callbackName, script, newInfo, mydata, allMatches; // Get a random name for the callback callbackName = "checkGames" + new Date().getTime() + Math.floor(Math.random() * 10000); // create the jsonP script call on the page script = document.createElement('script'); script.src = "http://www.hookhockey.com/index.php/temp-gillian/?callback=" + callbackName; document.documentElement.appendChild(script); // call the json window[callbackName] = function (data) { responseJsonVar = data; // this is the info back from the json file //the filtered data source from json AppInfo.allMatches = responseJsonVar["matches"]; // store data in allMatches property console.dir('allMatches inside the function: ' + AppInfo.allMatches); //this comes back fine AppInfo.confirmDataAvailableOutsideFunction(); // call test method to verify allMatches property is set // Remove our callback ('delete' with 'window properties fails on some versions of IE, so we fall back to setting the property to 'undefined' if that happens) try { delete window[callbackName]; } catch (e) { window[callbackName] = undefined; } //I've tried putting a return value (return allMatches) in here and then calling window[callbackName]() outside of the function but I get undefined for matches }; // end window[callbackName] function //this is what I think I should be doing to get the info out on its own console.dir('AppInfo.allMatches OUTSIDE the function BEFORE jsonp call executes: ' + AppInfo.allMatches); //this doesn't come back 'allMatches is not defined' } //end getdata method }; //end AppInfo AppInfo.getData();的文本以指示它在 jsonp调用返回之前正在运行，因此console.dir属性仍然是{{1}那时候。

这就是为什么在实施@ peter-b的建议后使用allMatches代替局部变量null，window.allMatches OUTSIDE函数是allMatches - 你正在检查它在它成立之前。

@ peter-b的解决方案可以正常工作，只要您在设置之前没有尝试访问window.allMatches。因此，如果您希望数据存储在全局变量中，您可以使用他的方法;如果您希望将其存储在AppInfo对象中，则可以使用我的。

或者，您可以将所有内容包装在具有undefined作为局部变量的立即函数中：

window.allMatches

Answer 2

获得所需内容的一种简单方法是将allMatches指定为window的属性，使其随处可访问。替换

var allMatches = responseJsonVar["matches"];

与

window.allMatches = responseJsonVar["matches"];

然后使用window.allMatches访问它。

方法之外的可变内容

2 个答案: