TabMenu.Registry = []
TabMenu.aniLen = 250
TabMenu.hideDelay = 1000
TabMenu.minCPUResolution = 10

// constructor
function TabMenu(id, dir, left, top, width, height)
{
        this.ie  = document.all ? 1 : 0
        this.ns4 = document.layers ? 1 : 0
        this.dom = document.getElementById ? 1 : 0

        if (this.ie || this.ns4 || this.dom) {
                this.id                  = id
                this.dir                 = dir
                this.orientation = dir == "left" || dir == "right" ? "h" : "v"
                this.dirType     = dir == "right" || dir == "down" ? "-" : "+"
                this.dim                 = this.orientation == "h" ? width : height
                this.hideTimer   = false
                this.aniTimer    = false
                this.open                = false
                this.over                = false
                this.startTime   = 0

                // global reference to this object
                this.gRef = "TabMenu_"+id
                eval(this.gRef+"=this")

                // add this menu object to an internal list of all menus
                TabMenu.Registry[id] = this

                var d = document
                d.write('<style type="text/css">')
                d.write('#' + this.id + 'Container { visibility:hidden; ')
                d.write('left:' + left + 'px; ')
                d.write('top:' + top + 'px; ')
                d.write('overflow:hidden; }')
                d.write('#' + this.id + 'Container, #' + this.id + 'Content { position:absolute; ')
                d.write('width:' + width + 'px; ')
                d.write('height:' + height + 'px; ')
                d.write('clip:rect(0 ' + width + ' ' + height + ' 0); ')
                d.write('}')
                d.write('</style>')

                this.load()
        }
}

TabMenu.prototype.load = function() {
        var d = document
        var lyrId1 = this.id + "Container"
        var lyrId2 = this.id + "Content"
        var obj1 = this.dom ? d.getElementById(lyrId1) : this.ie ? d.all[lyrId1] : d.layers[lyrId1]
        if (obj1) var obj2 = this.ns4 ? obj1.layers[lyrId2] : this.ie ? d.all[lyrId2] : d.getElementById(lyrId2)
        var temp

        if (!obj1 || !obj2) window.setTimeout(this.gRef + ".load()", 100)
        else {
                this.container  = obj1
                this.menu               = obj2
                this.style              = this.ns4 ? this.menu : this.menu.style
                this.homePos    = eval("0" + this.dirType + this.dim)
                this.outPos             = 0
                this.accelConst = (this.outPos - this.homePos) / TabMenu.aniLen / TabMenu.aniLen 

                // set event handlers.
                if (this.ns4) this.menu.captureEvents(Event.MOUSEOVER | Event.MOUSEOUT);
                this.menu.onmouseover = new Function("TabMenu.showMenu('" + this.id + "')")
                this.menu.onmouseout = new Function("TabMenu.hideMenu('" + this.id + "')")

                //set initial state
                this.endSlide()
        }
}
        
TabMenu.showMenu = function(id)
{
        window.status = id
        var reg = TabMenu.Registry
        var obj = TabMenu.Registry[id]
        
        if (obj.container) {
                obj.over = true

                // close other menus.
                for (menu in reg) if (id != menu) TabMenu.hide(menu)

                // if this menu is scheduled to close, cancel it.
                if (obj.hideTimer) { reg[id].hideTimer = window.clearTimeout(reg[id].hideTimer) }

                // if this menu is closed, open it.
                if (!obj.open && !obj.aniTimer) reg[id].startSlide(true)
        }
}

TabMenu.hideMenu = function(id)
{
        // schedules the menu to close after <hideDelay> ms, which
        // gives the user time to cancel the action if they accidentally moused out
        var obj = TabMenu.Registry[id]
        if (obj.container) {
                if (obj.hideTimer) window.clearTimeout(obj.hideTimer)
                obj.hideTimer = window.setTimeout("TabMenu.hide('" + id + "')", TabMenu.hideDelay);
        }
}

TabMenu.hide = function(id)
{
        var obj = TabMenu.Registry[id]
        obj.over = false

        if (obj.hideTimer) window.clearTimeout(obj.hideTimer)
        
        // flag that this scheduled event has occured.
        obj.hideTimer = 0

        // if this menu is open, close it.
        if (obj.open && !obj.aniTimer) obj.startSlide(false)
}

TabMenu.prototype.startSlide = function(open) {
        this.open = open
        if (open) this.setVisibility(true)
        this.startTime = (new Date()).getTime() 
        this.aniTimer = window.setInterval(this.gRef + ".slide()", TabMenu.minCPUResolution)
}

TabMenu.prototype.slide = function() {
        var elapsed = (new Date()).getTime() - this.startTime
        if (elapsed > TabMenu.aniLen) this.endSlide()
        else {
                var d = Math.round(Math.pow(TabMenu.aniLen-elapsed, 2) * this.accelConst)
                if (this.open && this.dirType == "-")           d = -d
                else if (this.open && this.dirType == "+")      d = -d
                else if (!this.open && this.dirType == "-")     d = -this.dim + d
                else                                                                            d = this.dim + d

                this.moveTo(d)
        }
}

TabMenu.prototype.endSlide = function() {
        this.aniTimer = window.clearTimeout(this.aniTimer)
        this.moveTo(this.open ? this.outPos : this.homePos)
        if (!this.open) this.setVisibility(false)
        if ((this.open && !this.over) || (!this.open && this.over)) {
                this.startSlide(this.over)
        }
}

TabMenu.prototype.setVisibility = function(bShow) { 
        var s = this.ns4 ? this.container : this.container.style
        s.visibility = bShow ? "visible" : "hidden"
}
TabMenu.prototype.moveTo = function(p) { 
        this.style[this.orientation == "h" ? "left" : "top"] = p
}
TabMenu.prototype.getPos = function(c) {
        return parseInt(this.style[c])
}