Div Question

I have started creating a calculator - link here: http://newfounddisposal.ca/rate-calc/calc.php
When user clicks on calculate button, a message displays showing the contents of the 1st textbox (math not done yet)
After a period oif 10 seconds, the red message disappears.

Then prob comes in when the user clicks the calculate button again - red message displays
but doesn’t disappear after 10 seconds.

Can’t figure out what the prob is

I checked the source for the link you provided but found no code that hides the #results DIV, is there a certain location in your code I should be looking at as nothing stands out.