URL and Multiple tabs issue

Hello all
i have 2 questions:

1. How to detect URL manipulation?
2. How to detect multiple tabs in the browser window. For eg: if there are 2 tabs already opened in the browser, say tab1 has google.com and tab2 has yahoo.com. I come on 3 tab. now on page load of tab 3 i want to know wat is opened in tab1 and tab2. can i achieve this?


Thanks



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