Mobile Browser Detect View

I have a call button on my site <a href="tel:888开发者_运维知识库4445555" ...

I want to detect when the user comes back to my page.

So let's say they are on the call for 2 minutes and they come back to the page.

Is there a way to detect this? I am strictly speaking on at least Android And/Or Iphone platforms.

1. Set tracking cookie.
2. Intercept link click event using JavaScript and set another cookie with timestamp
3. If page is loaded again check for existing cookies