Email Client Template

Is it possible to use Script Include or <script> within HTML in "Email Client Template" Module?

When I try to using <script> tag , after saving the source code/ template , the <script> tag doesn't support.

When I try to click on incident three dot, the compose email - template must be dynamically based on user role  .It must restrict based on user's role in  TO,CC,BCC. how this can be achieved?