Mixed Content Warnings

Mixed Content Warnings

Mixed content errors occur when HTTPS pages load resources over insecure HTTP connections. Modern browsers block active mixed content (scripts, stylesheets) by default while warning about passive mixed content (images, videos). Console messages indicate "Mixed Content: The page was loaded over HTTPS, but requested an insecure resource." These warnings compromise security assurances and may break site functionality.

Common sources include hardcoded HTTP URLs in HTML, CSS, or JavaScript files, third-party resources only available via HTTP, content management systems with HTTP URLs in databases, and dynamically generated content creating HTTP links. The problem often emerges during HTTPS migrations when resource URLs aren't comprehensively updated. User-generated content with embedded HTTP resources creates ongoing challenges.

Identifying mixed content requires systematic review using browser developer tools. The Console tab lists all mixed content warnings with specific URLs. The Network tab can filter by protocol to show remaining HTTP requests. For comprehensive detection across entire sites, use automated scanning tools or Content Security Policy reporting to log violations without blocking resources during investigation.

Fixing mixed content requires updating all HTTP references to HTTPS. Use protocol-relative URLs (//example.com/resource) or explicit HTTPS URLs. Update databases using search-and-replace queries, carefully handling serialized data. Modify templates and source code to generate HTTPS URLs. For third-party resources unavailable via HTTPS, consider hosting locally or finding alternatives. Content Security Policy headers with upgrade-insecure-requests can automatically upgrade HTTP requests during transition periods.