获取浏览器当前缩放比例

转自：https://blog.csdn.net/ddr66288/article/details/102119975

function detectZoom() {
            var ratio = 0,
                screen = window.screen,
                ua = navigator.userAgent.toLowerCase();

            if (window.devicePixelRatio !== undefined) {
                ratio = window.devicePixelRatio;
            } else if (~ua.indexOf('msie')) {
                if (screen.deviceXDPI && screen.logicalXDPI) {
                    ratio = screen.deviceXDPI / screen.logicalXDPI;
                }
            } else if (window.outerWidth !== undefined && window.innerWidth !== undefined) {
                ratio = window.outerWidth / window.innerWidth;
            }

            if (ratio) {
                ratio = Math.round(ratio * 100);
            }

            alert(ratio);
};

detectZoom();