移动端touch滑屏事件

<script>
    var windowHeight = $(window).height(),
            $body = $("body");
//     console.log($(window).height());
//     console.log($(‘body‘).height());
    $body.css("height", windowHeight);
//    console.log($(‘body‘).height());

    $("body").on("touchstart", function(e) {
        e.preventDefault();
        startX = e.originalEvent.changedTouches[0].pageX,
                startY = e.originalEvent.changedTouches[0].pageY;
    });
    $("body").on("touchmove", function(e) {
        e.preventDefault();
        moveEndX = e.originalEvent.changedTouches[0].pageX,
                moveEndY = e.originalEvent.changedTouches[0].pageY,
                X = moveEndX - startX,
                Y = moveEndY - startY;

        if ( Math.abs(X) > Math.abs(Y) && X > 10 ) {
            alert("left 2 right");
        }
        else if ( Math.abs(X) > Math.abs(Y) && X < 10 ) {
            alert("right 2 left");
        }
        else if ( Math.abs(Y) > Math.abs(X) && Y > 10) {
            alert("top 2 bottom");
        }
        else if ( Math.abs(Y) > Math.abs(X) && Y < 10 ) {
            alert("bottom 2 top");
        }
        else{
            alert("just touch");
        }
    });
</script>