除了Firefox之外，为什么（window.innerwidth＆gt; 1025）可以在所有浏览器中使用？

Question

我正在使用（window.innerwidth＆gt; 1025）来允许大于1025px宽的窗口中的视差代码。这适用于除Firefox之外的所有浏览器（Chrome，IE，Safari）。

当我删除第一行时，视差在Firefox中按预期工作。

if (window.innerWidth > 1025){      
        var $window = $(window);
        var windowHeight = $(window).height();
        var pos = $window.scrollTop(); //position of the scrollbar
        var $this = $(this);

        //setup defaults if arguments aren't specified
        if(xpos == null){xpos = "50%"}
        if(adjuster == null){adjuster = 0}
        if(inertia == null){inertia = 0.1}
        if(outerHeight == null){outerHeight = true}

        height = $this.height();
        $this.css({'backgroundPosition': newPos(xpos, outerHeight, adjuster, inertia)}); 

        function newPos(xpos, windowHeight, pos, adjuster, inertia){
            return xpos + " " + Math.round((-((windowHeight + pos) - adjuster) * inertia)) + "px";
        }

        //function to be called whenever the window is scrolled or resized
        function move(pos, height){ 
                $this.css({'backgroundPosition': newPos(xpos, height, pos, adjuster, inertia)}); 
        }

        $window.bind('scroll', function(){ //when the user is scrolling...

            pos = $window.scrollTop(); //position of the scrollbar
            inView(pos, $this);

        })

    }