当我用new关键字初始化一个变量（backbone.js模型）时，它在所有最新的浏览器（chrome和firefox）中都有效。但在Firefox41中却无效。

var backboneModel = new BackboneModel();

控制台中的错误（仅firefox41）为

TypeError: BackboneModel is not a constructor

有线索吗？

更新

我成功回调了导致此问题的原因。在new Blob语句之后出现以下错误

SyntaxError: missing ; before statement

于

success: function(model, response){
                     // Create a new Blob object using the 
                     //response data of the onload object
                     var blob = new Blob([response], {type: 'text/csv'});
                     //Create a link element, hide it, direct 
                     //it towards the blob, and then 'click' it programatically
                     let a = document.createElement("a");
                     a.style = "display: none";
                     document.body.appendChild(a);
                     //Create a DOMString representing the blob 
                     //and point the link element towards it
                     let url = window.URL.createObjectURL(blob);
                     a.href = url;
                     a.download = 'Sample_Report.csv';
                     //programatically click the link to trigger the download
                     a.click();
                     //release the reference to the file by revoking the Object URL
                     window.URL.revokeObjectURL(url);
                }