How to properly use the .animate() function -- top

Question

Is this the proper way to use the .animate(top) function?

Positive number (animate down)--

    $("div#container div#history-menu").animate({top:'180px'}, 600);

Negative number (animate up)--

    $("div#container div#history-menu").animate({top:'-180px'}, 600);

Because I'm getting a java error in my error console that says:

"error in parsing value for property 'top'. Declaration Dropped."

Answer 1

Changing the values from ({top: '-180px'}, 600) to ({top: '-=180'}, 600) or ({top:'+=180'},600) seems to eliminate my problem.