nextsibling error in crm 2016

Hi All,

 I am using CRM 2016, the below function are not working in crm 2016, which were working in the CRM 2015.

In a  script i am using "nextsibling" , onsave of the form it is throwing an error("Unable to get property 'nextSibling' of undefined or null reference").Can anyone help me on this.

Thanks,

Satya