The HTTP Content-Security-Policy (CSP) script-src-elem directive specifies valid sources for JavaScript <script> elements, but not inline script event handlers like onclick.
| CSP version | 3 | 
|---|---|
| Directive type | Fetch directive | 
| default-srcfallback | Yes. If this directive is absent, the user agent will look for the script-srcdirective, and if both of them are absent, fallback todefault-srcdirective. |