在GTM的数据层中使用时，Javascript变量未定义(Javascript variable undefined when used in data layer in GTM)

 我在GTM数据层中使用了一个从Liferay rest API调用中获取其值的变量。 
 
var openId;
AUI().ready('aui-base', function(A){
Liferay.Service(
       '/user/get-user-by-id',
        {
        userId: Liferay.ThemeDisplay.getUserId()
        },
        function(obj) {
          openId=obj.openId;
        }
                );
    });
 
 这里openId变量在GTM dataLayer中被使用，在那里它不可用并且显示为undefined 。 数据层定义如下： 
 
dataLayer = [{
                "page" : Liferay.currentURL
                ,"pageType" : instrDetail
                ,"user" : {
                            "type" : userType
                            ,"accountId" : openId
                          }
             }];
 
 最后，我们有GTM块，定义标签管理器脚本块。 
 
(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXX');
 
 现在，当我尝试访问dataLayer中的openId变量时，它显示为未定义，而当我尝试访问同一个浏览器控制台时，它显示正确的值。 

I am using a variable in GTM data layer which retrieves its value from Liferay rest API call.
 
var openId;
AUI().ready('aui-base', function(A){
Liferay.Service(
       '/user/get-user-by-id',
        {
        userId: Liferay.ThemeDisplay.getUserId()
        },
        function(obj) {
          openId=obj.openId;
        }
                );
    });
 
Here the openId variable is being used in GTM dataLayer,where it is not available and shows as undefined. The data layer is defined as below:
 
dataLayer = [{
                "page" : Liferay.currentURL
                ,"pageType" : instrDetail
                ,"user" : {
                            "type" : userType
                            ,"accountId" : openId
                          }
             }];
 
and in the end,we have the GTM block,defining the tag manager script block.
 
(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXX');
 
Now,when I try to access the openId variable in dataLayer,it shows as undefined,whereas when I try to access the same one browser console,it displays the correct value.

原文：https://stackoverflow.com/questions/41738649