var menu = null;

function Menu(section,subsection,layeredFlash) {
/*
Funky animated menu object
==========================
Arguments:
-----------------
section       // (int) section (if any) to show as "highlighted" (fixed open, static)
subsection    // (int) subsection (if any) to highlight
layeredFlash  // (boolean) apply nav logic (or not) based on flash layering support - dependant also on flash embedding support
*/
var self = this;
this.menu = null;
this.menuID = 'menu'; // menu container element ID
if (typeof(layeredFlash) == 'undefined') {
	layeredFlash = false;
} else {
	// logical AND with flash support check
	// enable menu drop-down if flash not supported (but is flagged as being on this page)
	var flash
	//  layeredFlash &= flash.hasVersion(5);
}

this.containers = [];
this.frames = [1,2,3,4,5,6,7,8,9,10,9,8,7,6,5,4,3,2,1];
this.tweens = [];
this.menuGroups = [];
this.menuHeight = [];
this.menuItems = [];
this.items = [];
this.itemCount = 0;

this.createTweens = function() {
	// Generate array of pixel offsets for nav containers
	for (var i=0; i<this.containers.length; i++) {
		this.tweens[i] = [0];
		this.tmp = 0;
		menuOffset = ua.isIE?10:9;
		for (var j=0; j<this.frames.length; j++) {
			this.tmp += ((this.menuHeight[i]+menuOffset)*(this.frames[j]*.01));
			this.tweens[i][this.tweens[i].length] = parseInt(this.tmp);
		}
		this.tweens[i][this.tweens[i].length] = this.menuHeight[i]+menuOffset;
	}
}
  
this.findNode = function(n) {
	// find a non-text node
	if (!n || !n.nodeType) return null;
	while (n.nodeType==3 && n.parentNode) {
		n = n.parentNode;
	}
	return n;
}

this.isChildOfId = function(targetId, target) {
	if (!target) return false;
	do {
		if (target.id && target.id.indexOf(targetId)+1) {
			return true;
		} else if (target.parentNode) {
			target = target.parentNode;
		}
	} while (target.parentNode && target.parentNode.nodeName != 'BODY');
	return false;
}
  
this.init = function() {
	// Grab items and create menu item objects, assign event handlers
	this.menu = document.getElementById(this.menuID);
	itemsTmp = this.menu.getElementsByTagName('li');
	for (var i=0; i<itemsTmp.length; i++) {
		if (itemsTmp[i].className && itemsTmp[i].className.indexOf('nav-groups')+1) {
		this.menuGroups[this.menuGroups.length] = itemsTmp[i];
		// only add to item count if menu has sub-items
		if (this.menuGroups[this.menuGroups.length-1].getElementsByTagName('ul').length) this.itemCount++;
		}
	}
	if (this.supported) {
		// remove CSS offset for static containers
		for (i=0; i<this.itemCount; i++) {
			if (section != i) {
			// don't remove padding from "stuck" open section
			document.getElementById('sub-group'+i).style.paddingTop = '0px';
			} else if (section == i && subsection+1) {
			// show highlighted sub-menu item, if applicable
			document.getElementById('nav-group'+i).getElementsByTagName('a')[subsection].className = 'active';
			}
		}
	}
	for (i=0; i<this.itemCount; i++) {
		// create container objects and nav item objects
		this.containers[i] = this.menuGroups[i].getElementsByTagName('ul')[0];
		this.menuHeight[i] = this.containers[i].offsetHeight; // height plus offset of margin
		this.menuItems[i] = new this.MenuItem(i);
		if (this.supported) {
			// supported browsers: assign animation event handlers or show static based on global "section" variable
			this.menuItems[i].show();
			if (section !=i) {
				// roll up menu if not selected
				this.containers[i].style.marginTop = ((this.menuHeight[i])*-1)+'px';
			}
		} else {
			// unsupported browsers: point to static show/hide function instead
			this.menuItems[i].move = this.menuItems[i].moveStatic;
			if (section == i && subsection+1) {
				document.getElementById('nav-group'+i).getElementsByTagName('a')[subsection].className = 'active';
			}
		}
		if ('nav-group'+section != this.menuGroups[i].id) {
			// Assign event handler to top-level anchor tag
			handler = this.menuItems[i].eventHandler;
			this.menuGroups[i].getElementsByTagName('a')[0].onmouseover = handler;
			this.menuGroups[i].getElementsByTagName('a')[0].onmouseout = handler;
			this.menuGroups[i].getElementsByTagName('div')[1].onmouseout = handler;
		} else {
			// do not assign event handlers - show nav and leave open
			this.menuItems[i].show();
		}
	}
}
  
this.ns6Fix = function() {
	// netscape 6.x "invisible links/disappearing float" nav workaround (strange browser bug?)
	// fix: change a display property of menu container (causing a reflow)
	document.getElementById(this.menuID).style.width='100%';
}
  
this.MenuItem = function(menuIndex) {
	this.direction = null;
	this.menuIndex = menuIndex;
	this.frameIndex = 0;
	this.defaultClassName = '';
	this.timers = [];
	this.active = 0;
	var me = this;
    
	this.animate = function() {
		if (this.frameIndex<0 || this.frameIndex>self.tweens[this.menuIndex].length) {
			this.frameIndex = 0;
		} else {
			if (this.frameIndex >= self.tweens[this.menuIndex].length) {
			} else {
			self.containers[this.menuIndex].style.marginTop = (self.menuHeight[menuIndex]*-1)+(this.direction==1?0:-1)+(self.tweens[this.menuIndex][this.frameIndex])-8+'px';
			}
		}
		this.frameIndex += this.direction;
	}

	this.reset = function(msg) {
		// reset after previous animation
		this.active = 0;
		this.timers = [];
		// catch potential frame mis-counts from excessive event firing
		if (this.frameIndex >= self.tweens[this.menuIndex].length) {
			this.frameIndex = self.tweens[this.menuIndex].length-1;
		}
	}
    
	this.clearTimers = function() {
		for (var i=0; i<this.timers.length; i++) {
			clearTimeout(this.timers[i]);
		}
		this.timers = [];
	}

	this.eventHandler = function(e) {
		e = e||window.event;
		if (e.relatedTarget || e.target) {
			var eRelatedTarget = self.findNode(e.relatedTarget);
			var eTarget = self.findNode(e.target);
		}
		if (e.type == 'mouseover' && !e.srcElement) {
			// W3C-style mouseover
			if (e.target == this) {
				me.move(1);
			} else if (e.target) {
			// me.move(1,e);
		}
		} else if (e.type == 'mouseover') {
			// IE-style mouseover
			me.move(1);
		} else if (e.type == 'mouseout' && !e.srcElement) {
			// W3C-style mouseout
			if (e.target == this) {
				if (!menu.isChildOfId('nav-group'+me.menuIndex,eRelatedTarget)) {
				me.move(-1);
				}
			} else if (!menu.isChildOfId('nav-group'+me.menuIndex,eRelatedTarget)) {
				// not related, nor a child.
				me.move(-1);
			}
		} else if (e.type == 'mouseout') {
			// IE-style mouseout
			if (!menu.isChildOfId('nav-group'+me.menuIndex,e.toElement)) {
				me.move(-1);
			}
		}
	}
    
	this.hide = function() {
		with (self.containers[me.menuIndex].style) {
			if (visibility != 'hidden') visibility = 'hidden';
		}
	}
    
	this.show = function() {
		with (self.containers[me.menuIndex].style) {
			if (visibility != 'visible') visibility = 'visible';
		}
	}
    
	this.moveStatic = function(direction,evt) {
		if (direction==1) {
			me.show();
		} else {
			me.hide();
		}
	}
    
	this.move = function(direction) {
		if (this.active == 0) {
			// not currently moving
			this.clearTimers();
			if (this.frameIndex>1 && direction==1) {
				return false;
			} 
			this.active = 1;
			this.direction = direction;
			this.timeout = 0;
			for (var i=0; i<self.tweens[this.menuIndex].length; i++) {
				this.timeout += 20;
				this.timers[this.timers.length] = setTimeout("menu.menuItems["+this.menuIndex+"].animate()",this.timeout);
			}
			this.timers[this.timers.length] = setTimeout("menu.menuItems["+this.menuIndex+"].reset()",this.timeout);
		} else {
			// nav is currently moving
			this.clearTimers();
			this.reset();
			this.timeout = 0;
			this.direction = (this.direction==-1?1:-1);
			if (this.direction==1) {
				for (var i=this.frameIndex; i<self.tweens[this.menuIndex].length; i++) {
					this.timeout += 20;
					this.timers[this.timers.length] = setTimeout("menu.menuItems["+this.menuIndex+"].animate()",this.timeout);
				}
			} else {
				for (var i=this.frameIndex; i>0; i--) {
					this.timeout += 20;
					this.timers[this.timers.length] = setTimeout("menu.menuItems["+this.menuIndex+"].animate()",this.timeout);
				}
		}
		this.timers[this.timers.length] = setTimeout("menu.menuItems["+this.menuIndex+"].reset()",this.timeout);
	}
}

} // MenuItem

// Menu() constructor

// determine browser type, assign animate handlers only where supported
this.supported = true;

if (ua.isMac && layeredFlash) {
	// Mac has issues with reliably layering HTML overtop of Flash - disable nav dropdown
	this.supported = false;
//	return null; //苹果会直接显示菜单
}

if (ua.isMac && (ua.isSafari || ua.isIE || ua.equivalentMozilla < 1.0)) {
	this.supported = false;
} else if (ua.isMac && ua.equivalentMozilla>=1.1 && !layeredFlash) {
	this.supported = true;
} else if (ua.isMac) {
	this.supported = false;
} else if (ua.isWin32) {
	if ((ua.isNS && ua.equivalentMozilla<1.1) || ua.isNS6x) {
	this.supported = false;
	}
}

if (ua.isNS6x) {
	// check for netscape 6 display bug
	setTimeout("menu.ns6Fix()",20); // give time to react - may be related to dynamic flash insert
	// and now, back to your regularly-scheduled menu script.
}

if (layeredFlash) {
	// test for flash "layering" support
	if (ua.isWin) {
		if (!ua.isNS && !ua.isIE && !ua.isOpera && !ua.isSafari && !ua.equivalentMozilla) {
		return false;
		}
	}
	if (ua.isNS && ua.equivalentMozilla < 1) {
		return false;
	}
}
//	if(ua.isMac)this.supported = true;
	this.init();
	this.createTweens();
}