window缩放150%前端适配

window缩放125% 150% ...以及 Retina屏前端适配

      (function () {
        var ratio = 0,
        screen = window.screen,
        ua = navigator.userAgent.toLowerCase();
        let view = document.querySelector('body');
    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 !== 1) {
        if (ratio >= 2) {
            ratio = ratio / 2
        } else if (ratio >= 3) {
            ratio = ratio / 3
        }
        view.style.zoom = -0.62 * ratio + 1.65;
    }
    console.log("dpi", ratio)
})(window);