How can content-clau be avoided when using scripts from external sources in PHP applications?

Content-clau issues can be avoided by using the `Content-Security-Policy` header in PHP applications. This header allows you to control from which sources scripts can be loaded, thereby preventing malicious scripts from being executed. By setting the `Content-Security-Policy` header to only allow scripts from trusted sources, you can mitigate the risk of content-clau attacks.

header("Content-Security-Policy: script-src 'self' https://trusted-source.com");