source: BMXNET_RPMS_dotNET_UTILITIES-BMX/branch/IHS BMX Framework/IndianHealthService.BMXNet.Doc/Help/Scripts/Dropdown.js@ 1187

        // Dropdown menu control

        function Dropdown(activatorId, dropdownId) {

                // store activator and dropdown elements
                this.activator = document.getElementById(activatorId);
                this.dropdown = document.getElementById(dropdownId);

                // wire up show/hide events
                registerEventHandler(this.activator,'mouseover', getInstanceDelegate(this, "show"));
                registerEventHandler(this.activator,'mouseout', getInstanceDelegate(this, "requestHide"));
                registerEventHandler(this.dropdown,'mouseover', getInstanceDelegate(this, "show"));
                registerEventHandler(this.dropdown,'mouseout', getInstanceDelegate(this, "requestHide"));

                // fix visibility and position
                this.dropdown.style.visibility = 'hidden';
                this.dropdown.style.position = 'absolute';
                this.reposition(null);

                // wire up repositioning event
                registerEventHandler(window, 'resize', getInstanceDelegate(this, "reposition"));


        }

        Dropdown.prototype.show = function(e) {
                clearTimeout(this.timer);
                this.dropdown.style.visibility = 'visible';
        }

        Dropdown.prototype.hide = function(e) {
                this.dropdown.style.visibility = 'hidden';
        }

        Dropdown.prototype.requestHide = function(e) {
                this.timer = setTimeout( getInstanceDelegate(this, "hide"), 250);
        }

        Dropdown.prototype.reposition = function(e) {

                // get position of activator
                var offsetLeft = 0;
                var offsetTop = 0;
                var offsetElement = this.activator;
                while (offsetElement) {
                        offsetLeft += offsetElement.offsetLeft;
                        offsetTop += offsetElement.offsetTop;
                        offsetElement = offsetElement.offsetParent;
                }

                // set position of dropdown relative to it
                this.dropdown.style.left = offsetLeft;
                this.dropdown.style.top = offsetTop + this.activator.offsetHeight;

        }