Error in Sale invoice form

1

Hi, everyone ,I getting an error of VM8761:343 Uncaught TypeError: Cannot read property 'extend' of undefined,
when I am routing to Sale invoice from any another form or trying to create a fresh sale invoice form.
The output of this error is :

Pasted image719×213 14.7 KB
.
Please suggest some solution
thanks
Baljeet Singh

2

Did you do any customization? And are you on the latest version?

3

@KanchanChauhan
Yes, I have add some custom fields in sale invoice form.
But its work previously with out any error.
still its work in between but getting this error most of the time.