CSP — Complete Guide
CSP — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of JavaScript Tutorial on Toolliyo Academy.
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JavaScript Tutorial · Lesson 78 of 100
CSP
Basics ✓ → Objects & data ✓ → Async & DOM ✓ → Advanced ✓ → Tools → Projects
Advanced · 5 — Testing & tools · ~10 min · JS Performance & Security
What is this?
Content Security Policy (CSP) is an HTTP header listing allowed script and style sources — blocks injected inline script.
Why should you care?
Even if XSS slips in, strict CSP can stop execution.
See it live — copy this example
Paste into an HTML file or the browser console (F12). Use Run below when the live editor is available.
// Example header (set on server):
// Content-Security-Policy: default-src 'self'; script-src 'self'Run Example »
Edit the code below and click Run to see the result in Toolliyo’s live editor.
What happened?
- Browser refuses scripts not from allowed origins.
- Avoid unsafe-inline in production.
Practice next
- Read example Content-Security-Policy header.
- Start with Content-Security-Policy-Report-Only.
- Use nonces for required inline scripts.
- Add img-src restriction allowing only self and CDN host.
- Configure report-uri to collect violations in staging.
Remember
HTTP header rules Restrict script sources Report-only for testing
ScriptVerse admin hardening
Strict script-src self nonce blocks injected script even if XSS sanitization fails once.
Outcome: CSP is defense-in-depth for ScriptVerse admin surfaces.
Interview prep for this lesson
Practice these questions aloud after reading—each links to a full structured answer.
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