Allow single access at a time to a certain area on a page of my web application
<p>There is a web page in my application where when I click on a specific link on the page, a window pops up with a form. I want that when a user clicks on the specific link on the pagefor the pop up form, it checks to see if another user had already clicked on this link and is using the pop up form. If yes, then there should be a message displayed "This section is currently in use by another user". If no, then the current user can go ahead and click on the link for the pop up form to appear.</p>

<p>How do I do this?</p>
