可以滚动，但是看不到滚动条。前提是你必须在页面载入的时候将鼠标焦点对准到A2层上，如果焦点在A2层外，滚轮和下建无效。这个可以用js很容易做到。
方案2：直接把滚动条颜色设置和背景层一样。
可以用js或者css实现。js可以监听鼠标的onscroll滚轮事件，事件内可以阻止鼠标的滚轮默认事件。
css可以设置元素的"pointer-events"属性，设置为none则所有鼠标事件失效。
通过此函数可以获取到鼠标滚动事件，然后做平移就好了/** Event handler for mouse wheel event.
*鼠标滚动事件
*/
var wheel = function(event) {
var delta = 0
if (!event) /* For IE. */
event = window.event
if (event.wheelDelta) { /* IE/Opera. */
delta = event.wheelDelta / 120
} else if (event.detail) {
/** Mozilla case. */
/** In Mozilla, sign of delta is different than in IE.
* Also, delta is multiple of 3.
*/
delta = -event.detail / 3
}
/** If delta is nonzero, handle it.
* Basically, delta is now positive if wheel was scrolled up,
* and negative, if wheel was scrolled down.
*/
if (delta)
handle(delta)
/** Prevent default actions caused by mouse wheel.
* That might be ugly, but we handle scrolls somehow
* anyway, so don't bother here..
*/
if (event.preventDefault)
event.preventDefault()
event.returnValue = false
}
/** Initialization code.
* If you use your own event management code, change it as required.
*/
if (window.addEventListener) {
/** DOMMouseScroll is for mozilla. */
window.addEventListener('DOMMouseScroll', wheel, false)
}
/** IE/Opera. */
window.onmousewheel = document.onmousewheel = wheel
/** This is high-level function.
* It must react to delta being more/less than zero.
*/
var handle = function(delta) {
var random_num = Math.floor((Math.random() * 100) + 50)
if (delta <0) {
// alert("鼠标滑轮向下滚动：" + delta + "次！")// 1
$("btn_next_pic").onclick(random_num)
return
} else {
// alert("鼠标滑轮向上滚动：" + delta + "次！")// -1
$("btn_last_pic").onclick(random_num)
return
}
}
