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title: JavaScript之鼠标滚动事件 categories:

• JavaScript
• 杂物间 tags:
• tech
• cnblogs warning: true date: 2013-04-09 08:36:00 fromUrl: http://www.cnblogs.com/hustskyking/archive/2013/04/09/mousewheel.html from: 博客园

/**
 * This is high-level function.
 * It must react to delta being more/less than zero.
 */
function handle(delta) {
        if (delta < 0)
        ...;
        else
        ...;
}

/**
 * Event handler for mouse wheel event.
 */
function wheel(event){
    var delta = 0;
    if (!event) /* For IE. */
        event = window.event;
    if (event.wheelDelta) { /* IE/Opera. */
        delta = event.wheelDelta / 120;
        /**
         * In Opera 9, delta differs in sign as compared to IE.
         */
        if (window.opera)
            delta = -delta;
    }
    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;

<h3>Handler function 事件处理函数</h3>

/** 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;
            }
        }

<h3>Reference [参考]</h3>