/**
 * Adds and removes classes to a list of links to allow keyboard accessibility
 *taken from http://blakehaswell.com/lab/dropdown/deux/
 *
 * @param string dropDownId
 * @param string hoverClass
 * @param int mouseOffDelay
 */
function dropdown(dropdownId, hoverClass, mouseOffDelay) {
    if(dropdown = document.getElementById(dropdownId)) {
        var listItems = dropdown.getElementsByTagName('li');
        for(var i = 0, l = listItems.length; i < l; i++) {
            listItems[i].onmouseover = function() { 
                this.className = addClass(this); 
            }
            listItems[i].onmouseout = function() {
	        var that = this;
	        setTimeout(function() { 
                    that.className = removeClass(that); 
                    }, mouseOffDelay);
		this.className = that.className;
	    }
			
	    var anchor = listItems[i].getElementsByTagName('a');
	    anchor = anchor[0];
	    anchor.onfocus = function() { 
                tabOn(this.parentNode); 
            }
	    anchor.onblur = function() { 
                tabOff(this.parentNode); 
            }
	}
    }
	
    function tabOn(li) {
        if(li.nodeName == 'LI') {
            li.className = addClass(li);
            tabOn(li.parentNode.parentNode);
        }
    }
	
    function tabOff(li) {
        if(li.nodeName == 'LI') {
            li.className = removeClass(li);
            tabOff(li.parentNode.parentNode);
        }
    }
	
    function addClass(li) { 
        return li.className + ' ' + hoverClass; 
    }
    function removeClass(li) { 
        return li.className.replace(hoverClass, ""); 
    }

}