Popup DatePicker Showing Behind Applet When Moved

I have a DatePicker I position on the screen when an icon is pressed. Code is as follows:

var div = document.createElement("div");

var span = document.createElement("span");

span.id = calSpanID;

with (span.style) {position = "absolute"; left = (xpos8)'px'; top = (ypos-8)+'px'; width = CalWidth; border = "solid 2pt " + SpanBorderColor; padding = "0pt"; cursor = "move"; backgroundColor = SpanBgColor; zIndex = 100;}

div.appendChild(span);

document.body.appendChild(div);

winCal=document.getElementById(calSpanID);

When I move the popup around the screen or position it around an mii applet, it is behind the applet. I have messed with the zindex with no success.