title: Argument 2 of FormData.append is not an object in mozila firefox
body: <p>sending the file to back end with help of formData.append()(appending the document details).It is working fine in google chrome.but i having facing issue in mozila and safari with this error.</p>
  
  <p><a href="https://i.stack.imgur.com/Y70D1.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Y70D1.jpg" alt="enter image description here"></a></p>
  
  <p>Service Code:</p>
  
  <pre><code>  manageSingleDataWithChildModel(url: string, data: any, childData: any, docRefArea: string = ''): Observable&lt;any&gt; {
          this._spinnerService.show();
          this.refreshSession();
          var formData: FormData = new FormData();
          formData.append('docReferenceArea', docRefArea);
          childData.forEach((data: any) =&gt; { 
              if (data.DocumentDetails != null &amp;&amp; data.DocumentDetails.DocContent != null &amp;&amp; data.DocumentDetails.DocContent != "") {
                  data.FileIdentifier = data.DocumentDetails.FileIdentifier;
                  formData.append('files', data.DocumentDetails.DocContent, data.DocumentDetails.FileIdentifier);
                  data.DocumentDetails.DocContent = null;
              }
          });
          formData.append('dataModel', JSON.stringify(data));
  
          let headers = new Headers(
              {
                  'enctype': 'multipart/form-data',
                  'method': 'POST',
                  'Authorization': 'Bearer ' + localStorage.getItem('BearerToken'),
              });
          let options = new RequestOptions({ headers: headers });
          return this._http.post(url, formData, options)
              .map((res: Response) =&gt; { this._spinnerService.hide(); return HttpHelper.json(res) })
              .catch(error =&gt; this.handleError(error));
      }
  </code></pre>