Function getWheelDeltaMayPolyfill

_benchmarks/sample_echarts.js:1279–1295

(e)

        return e;
    }
    function getWheelDeltaMayPolyfill(e) {
        var rawWheelDelta = e.wheelDelta;
        if (rawWheelDelta) {
            return rawWheelDelta;
        }
        var deltaX = e.deltaX;
        var deltaY = e.deltaY;
        if (deltaX == null || deltaY == null) {
            return rawWheelDelta;
        }
        var delta = deltaY !== 0 ? Math.abs(deltaY) : Math.abs(deltaX);
        var sign = deltaY > 0 ? -1
            : deltaY < 0 ? 1
                : deltaX > 0 ? -1
                    : 1;
        return 3 * delta * sign;
    }
    function addEventListener(el, name, handler, opt) {
        if (isDomLevel2) {
            el.addEventListener(name, handler, opt);