How to add Serial No. to first column of specific Table only

[sinelogixtech]

I have many tables on dashboard also I have fullCalender(fullCalender uses table on UI) on dashboard. All I need is to have serial number in first column of specific table only, it can be identified by either id or class,

<style>
table { counter-reset: Serial; }
table { border-collapse: separate; }
tr td:first-child:before { counter-increment: Serial; content: counter(Serial).; }
</style>
but it give serial numbers to all the table that exists on UI including fullCalender.

[davidweb09]

You have use Java script to optimize this code.