Hi Rekha,
If you are using MS CRM on premise version you can have access to that location. This is a system file.
Assume your CRM is installed on C drive then the location will be.
C:\Program Files\Microsoft Dynamics CRM\CRMWeb\_static\_common\scripts
Note:making any change in CRM system files comes under unsupported customization.
Hope this helps,
Yusuf
If you find this post helpful then please "Vote as Helpful" and "Mark As Answer". Thanks and Regards, Mohammad Yusuf Ansari
http://microxrm.blogspot.in