function getMousePosition(e) { 
    if (e.pageX || e.pageY){ 
        var posX = e.pageX; 
        var posY = e.pageY; 
    }else if (e.clientX || e.clientY)     { 
        var posX = e.clientX + document.body.scrollLeft + document.documentElement.scrollLeft; 
        var posY = e.clientY + document.body.scrollTop + document.documentElement.scrollTop; 
    } 
    return {x:posX, y:posY}     
} 
var scrolltotop={ 
    setting: {startline:600, scrollduration:500, fadeduration:[500, 100]}, 
    controlHTML: '<img src="./pic/up.png" style="width:35px; height:35px" />', 
    controlattrs: {offsetx:15, offsety:50}, 
    anchorkeyword: '#atop', 
    state: {isvisible:false, shouldvisible:false}, 
    scrollup:function(){ 
        if (!this.cssfixedsupport) 
            this.$control.css({opacity:0}) 
        this.$body.animate({scrollTop: 0}, this.setting.scrollduration); 
    }, 
    keepfixed:function(){ 
        var $window=jQuery(window) 
        var controlx=$window.scrollLeft() + $window.width() - this.$control.width() - this.controlattrs.offsetx 
        var controly=$window.scrollTop() + $window.height() - this.$control.height() - this.controlattrs.offsety 
        this.$control.css({left:controlx+'px', top:controly+'px'}) 
    }, 
    togglecontrol:function(){ 
        var scrolltop=jQuery(window).scrollTop() 
        if (!this.cssfixedsupport) this.keepfixed() 
        this.state.shouldvisible=(scrolltop>=this.setting.startline)? true : false 
        if (this.state.shouldvisible && !this.state.isvisible){ 
            this.$control.stop().animate({opacity:1}, this.setting.fadeduration[0]) 
            this.state.isvisible=true 
        } 
        else if (this.state.shouldvisible==false && this.state.isvisible){ 
            this.$control.stop().animate({opacity:0}, this.setting.fadeduration[1]) 
            this.state.isvisible=false 
        } 
    }, 
    init:function(){ 
        jQuery(document).ready(function($){ 
            var mainobj=scrolltotop 
            var iebrws=document.all 
            mainobj.cssfixedsupport=!iebrws || iebrws && document.compatMode=="CSS1Compat" && window.XMLHttpRequest 
            mainobj.$body=$('html,body') 
            mainobj.$control=$('<div id="topcontrol">'+mainobj.controlHTML+'</div>') 
                .css({position:mainobj.cssfixedsupport? 'fixed' : 'absolute', bottom:mainobj.controlattrs.offsety, right:mainobj.controlattrs.offsetx, opacity:0, cursor:'pointer'}) 
                .click(function(){mainobj.scrollup(); return false}) 
                .appendTo('body') 
            if (document.all && !window.XMLHttpRequest && mainobj.$control.text()!='') 
                mainobj.$control.css({width:mainobj.$control.width()}) 
            mainobj.togglecontrol() 
            $('a[href="' + mainobj.anchorkeyword +'"]').click(function(){ 
                mainobj.scrollup() 
                return false 
            }) 
            $(window).bind('scroll resize', function(e){ 
                mainobj.togglecontrol() 
            }) 
        }) 
    } 
} 
scrolltotop.init()