判断鼠标滚轮的滚动方向

function mousewheelHandler(e){

var delta = Math.max(-1, Math.min(1, (e.wheelDelta || -e.detail)));

console.log(delta > 0 ? "向上滚动" : "向下滚动");

}

 

//for Firefox

document.addEventListener("DOMMouseScroll", mousewheelHandler, false);

 

//for Chrome Safari

document.addEventListener("mousewheel", mousewheelHandler, false);