Check ongoing navigation before proceeding with javascript: URL navigation

[byteforge38]

The "navigate to a javascript: URL" algorithm now receives the navigationId from the navigate algorithm and checks if the ongoing navigation is still the same before proceeding. This ensures that javascript: URL navigations do not interfere with other navigations that may have started in the meantime (e.g., form submissions).

Fixes #12075.

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• At least two implementers are interested (and none opposed):
  • N/A
• Tests are written and can be reviewed and commented upon at:
  • https://github.com/web-platform-tests/wpt/blob/master/html/semantics/forms/form-submission-0/jsurl-navigation-then-form-submit.html (existing)
• Implementation bugs are filed:
  • Chromium: N/A
  • Gecko: N/A
  • WebKit: N/A
• MDN issue is filed: N/A
• The top of this comment includes a clear commit message to use.

(See WHATWG Working Mode: Changes for more details.)

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/browsing-the-web.html ( diff )

[annevk]

I think this works, thanks! This is already implemented by all browsers, right?

cc @josepharhar

[byteforge38]

@annevk Thanks for reviewing and approving my PR. The Participation CI check asks me to get verified. Could you please verify me so that it can succeed?

[josepharhar]

This ensures that javascript: URL navigations do not interfere with other navigations that may have started in the meantime (e.g., form submissions).

The commit message which I added this test in suggests that form submissions cancel pending js url navigations rather than js url navigations checking if there is any other pending navigation and canceling itself, but I also don't know what a navigation id is 😅

[annevk]

This accomplishes that:

1. You navigate to a JS URL. This sets the current navigation ID (let's say to JSURL) and queues a task passing on JSURL.
2. You navigate a form. This sets the current navigation ID to FORM and queues its own task.
3. The JS URL task now runs. It looks at the current navigation ID to see if it's still JSURL. It's not, so it returns early.