页面生成图片修改

@@ -1454,6 +1454,9 @@
                 success: function (res) {
                     img_url = res.data;
                     $('.view_img').css('display','block');
+                },
+                error: function (XMLHttpRequest, textStatus, errorThrown) {
+                    alert(XMLHttpRequest.status+" "+XMLHttpRequest.readyState+" "+textStatus);
                 }
             });
             // document.querySelector(".down").setAttribute('href', canvas.toDataURL());