Before we begin, here is exactly what you will be able to do by the end of this lesson.
By the end of this lesson, you will be able to:
- Define a web origin as the exact combination of scheme, host, and port — and state that all three components must match for two URLs to be considered the same origin.
- Determine whether two given URLs share the same origin, including cases involving different subdomains, schemes, and ports.
- Explain the Same-Origin Policy's core rule: a script running in one origin may read data from the same origin but not from a different origin.
- State the critical gap the SOP leaves: it blocks reading cross-origin responses but does not block sending cross-origin requests — the gap that CSRF exploits.
- Compare URL pairs in the custom Origin Inspector and trace a cross-origin read in the SOP Visualizer.
When you are ready, send Continue.