$(document).ready(function()
{

    $('.contentPanelHeader.collapsable').click(function()
    {
        var content = $(this).next();
        var collapsed = content.is(':hidden');
        var header = $(this);
        if(collapsed)
        {
            content.slideDown(600,function()
            {
                SwitchCollapsableHeaderClass(header,collapsed);
            });
        }
        else
        {
            content.slideUp(600,function()
            {
                SwitchCollapsableHeaderClass(header,collapsed);
            });
        }
        
    });
    
    function SwitchCollapsableHeaderClass(header,collapsed)
    {
        header.toggleClass('collapsed',!collapsed);
    }

});