i need JavaScript to add sequence based on value in last added item in sharepoint list


i need JavaScript to add sequence number based on sequence number in last added item (I do not want to use ID for increment in sequence )

Eg: Auto sequence column is with value 1 … on adding second item value on last item should be checked and sequence as 2 in new item . Since , Sequence column will get reset by workflow as 1 based on some condition i do not want to use ID as increment. I need JavaScript to add increatment value of 1 for new items

Please help.

Sharepoint 2013