Update sales_invoice.js
diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.js b/erpnext/accounts/doctype/sales_invoice/sales_invoice.js
index c5e9418..fda6548 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.js
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.js
@@ -103,7 +103,7 @@
 						company: cur_frm.doc.company
 					}
 				})
-			});
+			}, "icon-download", "btn-default");
 	},
 
 	delivery_note_btn: function() {
@@ -123,7 +123,7 @@
 						};
 					}
 				});
-			});
+			}, "icon-download", "btn-default");
 	},
 
 	tc_name: function() {