网页，鼠标滑动切换一屏

    var isFF=/FireFox/i.test(navigator.userAgent);
    var change = document.documentElement.clientHeight - 75;
    var scrollHeight = document.body.scrollHeight - change -75;
    var box = $('.wrapItem img').width();
    $('.headNav').css('width',box+'px')
    console.log(box)
    var now = 0;
    //如果不加时间控制，滚动会过度灵敏，一次翻好几屏
    var startTime = 0, //翻屏起始时间  
    endTime = 0;

    windowAddMouseWheel();
	function windowAddMouseWheel() {     
	    var scrollFunc = function (e) {
            e = e || window.event;
            startTime = new Date().getTime(); 
            if ((endTime - startTime) < -1000){
                if (e.wheelDelta) {  //判断浏览器IE，谷歌滑轮事件
                    if (e.wheelDelta > 0) { //当滑轮向上滚动时
                        now += change   
                        if(now <= 0){
                            toPage(now)
                        }else{
                            now -= change   
                        }
                        e.preventDefault();
                    }
                    if (e.wheelDelta < 0) { //当滑轮向下滚动时
                        now -= change
                        if(now >= -scrollHeight){
                            toPage(now)
                        }else{
                            now += change   
                        }
                        e.preventDefault();
                    }
                } else if (e.detail) {  //Firefox滑轮事件
                    if (e.detail> 0) { //当滑轮向上滚动时s
                        now -= change
                        if(now >= -scrollHeight){
                            toPage(now)
                        }else{
                            now += change   
                        }
                        e.preventDefault();   
                    }
                    if (e.detail< 0) { //当滑轮向下滚动时
                        now += change   
                        if(now <= 0){
                            toPage(now)
                        }else{
                            now -= change   
                        }
                        e.preventDefault();
                    }
                }
                endTime = new Date().getTime();  
            }else{  
                e.preventDefault();                
            } 

	};
				    //给页面绑定滑轮滚动事件
        if (!isFF) { 
            document.addEventListener('mousewheel', scrollFunc, { passive: false })
        }else{//火狐使用DOMMouseScroll绑定
            document.addEventListener('DOMMouseScroll', scrollFunc, false);
        }
        // window.onmousewheel = document.onmousewheel = scrollFunc;
    }
    function toPage(now){        
        $("#contanier").animate({top:(now+'px')},700);     //jquery实现动画效果
    }
    $('.nav a').on('click',function(){
        var index = $('.nav a').index(this)
        index > 1 ? (index+=2):''
        now = -(index*change)
        toPage(now)
    })
 
    window.onload = function(){
        setTimeout(function(){
            $(window).scrollTop(0)
        },10)
    }

效果图：