谷歌地图API GeoJSON不适用于IE 11，但适用于Chrome

我有一个谷歌地图，它从Visual Studio 2013中本地主机上运行的GeoJSON文件中加载标记。它也在chrome中运行（来自IIS服务器），但不会在IE版本11中运行。映射会显示，但JSON文件中的标记不会显示。为什么这在IIS 8上的Chrome和通过VS的IE 11中都能工作，而在IIS 8的IE 11中却不能工作？

    var map;
    var infowindow = new google.maps.InfoWindow({ });
    function initialize() {
            map = new google.maps.Map(document.getElementById('googleMap'), {
            center: new google.maps.LatLng(15.508742, -0.120850),
            zoom: 2,
            mapTypeId: google.maps.MapTypeId.HYBRID,
            scrollwheel: false 
        });
        google.maps.event.addListener(map, 'click', function() {
            infowindow.close();
        });
        // Load a GeoJSON from the same server as our demo.
        map.data.loadGeoJson('locations.json');
        // Set event listener for each feature.
        map.data.addListener('click', function (event) {
            infowindow.setContent("<div> " + event.feature.getProperty('city') + " " + event.feature.getProperty('date') + "<br>" + event.feature.getProperty('course') + "<br>Sponsored by: " + event.feature.getProperty('sponsor') + "<br>" + "<a href=" + "/Training.aspx" + ">Click here to Register</a>" + "</div>");
            infowindow.setPosition(event.latLng);
            infowindow.setOptions({ pixelOffset: new google.maps.Size(0, -34) });
            infowindow.open(map);
        });
        map.data.addListener('mouseover', function (event) {
            //infowindow.setContent("<div class='"map_info_box'" > " + event.feature.getProperty('city') + " " + event.feature.getProperty('date') + "<br>" + event.feature.getProperty('course') + "<br>Sponsored by: " + event.feature.getProperty('sponsor') + "<br>" + "<a href=" + "/Training.aspx" + ">Click here to Register</a>" + "</div>");
            infowindow.setContent("<div> " + event.feature.getProperty('city') + " " + event.feature.getProperty('date') + "<br>" + event.feature.getProperty('course') + "<br>Sponsored by: " + event.feature.getProperty('sponsor') + "<br>" + "<a href=" + "/Training.aspx" + ">Click here to Register</a>" + "</div>");
            infowindow.setPosition(event.latLng);
            infowindow.setOptions({ pixelOffset: new google.maps.Size(0, -34) });
            infowindow.open(map);
        });
    }
    google.maps.event.addDomListener(window, 'load', initialize);