Seeing as how you all seem to know now, except funny girl, that doesn't seem fair....
When the table seems to floats byitself a bar is inserted into a hole in the side of the table through the curtain in the background and lifted by an assistant at the back.
A more impressive trick is when the illusionist appears to be pushing down on the table but is in fact lifting the table with eight wire loops that are hidden among the floral pattern of th cloth, having one finger through each loop.