Function getNativeEvent

_benchmarks/sample_echarts.js:1251–1254

(e)

        out.zrX = out.zrY = 0;
    }
    function getNativeEvent(e) {
        return e
            || window.event;
    }
    function normalizeEvent(el, e, calculate) {
        e = getNativeEvent(e);
        if (e.zrX != null) {