Here's my test site: http://lushliving.sg/proto/listings/

I'm using Prototype's Ajax to update the Cart and do the form submit. Works in Firefox but in IE, my whole sidebar disappears.

The JS: http://lushliving.sg/proto/wp-content/themes/lushliving/js/cart.js

The strange thing is that when I call the function in the beginning

Event.observe(window, 'load', init, false);
function init() {
manageCart('display', '');
}
It works. The form submission also works. Only the add_item and remove_item functions that I call using onclick will cause the sidebar to disappear.

Hope someone who has JS knowledge can enlighten me on this.