How to run a task after the page being killed in browser?

Question

First of all, it has two pages: example.com/pageA and example.com/pageB, it's not a SPA.

How to run a delay task after the page being killed by history.back?

I tried using setTimeout but failed to execute the task after history.back, because the timer will be clear in stack when page change.

var a = 1

function refresh() {
  // <p id="count"></p>
  count.innerText = a
}

function foo() {
  a += 1
  refresh()
}

// called in PageB
function goBackA() {
  setTimeout(foo, 1000)
  history.back()
}

In PageA the count still be 1 instead of 2.

Answer 1

For security reason, your goal to run some code after page being killed will never be supported by the browser, because it's dangerous when some code can run on a different page.

Once the page being reload/killed, all the unfinished tasks will be clear even if in a SharedWorker.

So, two ways to accomplish your logic:

1. change to SPA
2. give another page a hint like query