How I can get the information of current working tab of a browser via Javascript?

[CetiN]

My web application have copy/paste functionality in browser so that end users can Ctrl+C one row from one table and then Ctrl+V to another table. I am recently facing some issues that were raised by customers, these are that users do copy/paste in two parallel browser windows or 2 Tabs in the same Window (either in safari or firefox). and that causes incorrect entries gets inserted in the table.I want prevent these kinds of incorrect entries. so the current solution I thought is to disable copy/paste across tabs or windows, I want to generate something like an id value which corresponds a tab of browser, so different tabs or different windows will definitely have different id values. when copying, I will put this id to the clipboard, when pasting I will validate the id so make sure they are coping/pasting on the same tab of same window.Do you guys think my idea is practicable? if so how I can generate this id by JavaScript, or in another word how I can use Javascript to get the information of current working tab of a browser? This is a very urgent issue to me any ideas would be appreciated.