If you want the element to disappear after a certain time, regardless of page reloads (that's the way I read your question), you would have to work with cookies.
You would have to set a cookie with the starting point
You would have to execute a JavaScript function on page load that compares the time set in the cookie with the current time, and shows/hides the element accordingly.
For a perfect solution, you would additionally implement a timer that compares the current date to the date in the cookie every, say, half-second, and hides the element when the time has been reached.
Using a framework like JQuery is certainly a good idea for this.
