show-when: a Web Component that conditionally shows or hides HTML content based on browser environment state.

Key features:

• URL query parameter matching (key or key=value)
• Hash-based visibility with live hashchange reaction
• CSS feature detection via CSS.supports()
• Media query matching with live updates
• Network status detection (online/offline)
• A companion hide-when element for inverted logic

Great for progressive enhancement, debug panels, offline notices, browser compatibility messages, and locale-based content blocks. No framework required.

Full setup guide, examples, and attribute reference: [https://www.cssscript.com/conditional-content-visibility-show-when/]