How Can I Reliably Get the Previous URL in JavaScript?

Determining the Previous URL in JavaScript

In JavaScript, obtaining the previous URL visited by a user can be tricky. However, several approaches can be employed.

Using document.referrer:

The document.referrer property provides the URL of the previous page if the user navigated to the current page via a hyperlink. It can be obtained as follows:

console.log("Previous URL: " + document.referrer);

Limitations of document.referrer:

• It is unreliable if the user types the URL directly into the address bar or submits a form.
• It is not accessible in some security-conscious browsers, such as Safari.

History Management with window.history:

window.history allows for manipulating the browser's history, but does not directly provide access to URLs. However, the history.state object can be used to store a custom URL property:

history.state = { prevUrl: location.href };

Then, you can retrieve it in the previous page:

const prevUrl = history.state && history.state.prevUrl;

Other Approaches:

• Cookies: Setting a cookie to store the previous URL is a viable option, but requires extra server-side logic.
• Parameter Tracking: Append a parameter to the current URL containing the previous URL, but this method can clutter the URL if the user navigates frequently.

Security Considerations:

Providing access to the previous URL raises security and privacy concerns, as it could allow malicious websites to track user browsing history. Therefore, browsers have implemented restrictions on URL accessibility.

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