SAP Javascript ENTER button does not work

Question

I have an application developed in javascript and adopted in SAP (BSP).

After system copy ENTER button is not working in system - when I change the data it is endless looping the loading.

code fragment for enter function:

function Enter(keycode) {
if (window.event.srcElement.type == "textarea" && keycode == 13 ) {
glLastKeycode = keycode;
keycode = 0;
} else {
glLastKeycode = keycode;
}
if (keycode == 13) {
write_wait();
window.external.AutoCompleteSaveForm(document.forms[0]);
document.forms[0].elements['event'].value='SPEICHERN';
document.forms[0].submit();

the picture how it is processing in app:

1. change quantity
2. ENTER button press