Problems with page.visual effect('Scale'..) in RJS

Rails
1

Have tried to scale an image in a div (divid) by using
page.visual_effect(‘Scale’, divid, :scaleTo => 200.0),
but it does not work
My tests show that there is something wrong with the scaleTo value
but I do not know if I use the wrong syntax (have tried many versions
of the syntax) orr if there is some othe problem
The style for the div is
#item_5 {
position:absolute;
left:410px;
top:230px;
height:60px;
width:80px;
z-index:2;
visibility:hidden;

Anyone that know what’s wrong !