如何在所有现代浏览器中检测页面缩放级别?虽然这篇文章讲述了如何在IE7和IE8中做到这一点,但我找不到一个好的跨浏览器解决方案。 Firefox存储页面缩放级别以供将来访问。在第一页加载,我能得到缩放级别吗?在某个地方,我读到当页面加载后发生缩放变化时,它是有效的。 有办法捕捉'缩放'事件吗?

我需要这个,因为我的一些计算是基于像素的,他们可能会在放大时波动。


@tfl给出的修改样本

放大时,此页面会提示不同的高度值。(jsFiddle)

<html>
    <head>
        <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.1/jquery.min.js" type="text/javascript"/></script>
    </head>
    <body>
        <div id="xy" style="border:1px solid #f00; width:100px;">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Pellentesque sollicitudin tortor in lacus tincidunt volutpat. Integer dignissim imperdiet mollis. Suspendisse quis tortor velit, placerat tempor neque. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Praesent bibendum auctor lorem vitae tempor. Nullam condimentum aliquam elementum. Nullam egestas gravida elementum. Maecenas mattis molestie nisl sit amet vehicula. Donec semper tristique blandit. Vestibulum adipiscing placerat mollis.</div>
        <button onclick="alert($('#xy').height());">Show</button>
    </body>
</html>

当前回答

试试这个

alert(Math.round(window.devicePixelRatio * 100));

其他回答

function supportFullCss3()
{
    var div = document.createElement("div");
    div.style.display = 'flex';
    var s1 = div.style.display == 'flex';
    var s2 = 'perspective' in div.style;

    return (s1 && s2);
};

function getZoomLevel()
{
    var screenPixelRatio = 0, zoomLevel = 0;

    if(window.devicePixelRatio && supportFullCss3())
        screenPixelRatio = window.devicePixelRatio;
    else if(window.screenX == '0')
        screenPixelRatio = (window.outerWidth - 8) / window.innerWidth;
    else
    {
        var scr = window.frames.screen;
        screenPixelRatio = scr.deviceXDPI / scr.systemXDPI;
    }

    //---------------------------------------
    if (screenPixelRatio <= .11){ //screenPixelRatio >= .01 &&
      zoomLevel = "-7";
    } else if (screenPixelRatio <= .25) {
      zoomLevel = "-6";
    }else if (screenPixelRatio <= .33) {
      zoomLevel = "-5.5";
    } else if (screenPixelRatio <= .40) {
      zoomLevel = "-5";
    } else if (screenPixelRatio <= .50) {
      zoomLevel = "-4";
    } else if (screenPixelRatio <= .67) {
      zoomLevel = "-3";
    } else if (screenPixelRatio <= .75) {
      zoomLevel = "-2";
    } else if (screenPixelRatio <= .85) {
      zoomLevel = "-1.5";
    } else if (screenPixelRatio <= .98) {
      zoomLevel = "-1";
    } else if (screenPixelRatio <= 1.03) {
      zoomLevel = "0";
    } else if (screenPixelRatio <= 1.12) {
      zoomLevel = "1";
    } else if (screenPixelRatio <= 1.2) {
      zoomLevel = "1.5";
    } else if (screenPixelRatio <= 1.3) {
      zoomLevel = "2";
    } else if (screenPixelRatio <= 1.4) {
      zoomLevel = "2.5";
    } else if (screenPixelRatio <= 1.5) {
      zoomLevel = "3";
    } else if (screenPixelRatio <= 1.6) {
      zoomLevel = "3.3";
    } else if (screenPixelRatio <= 1.7) {
      zoomLevel = "3.7";
    } else if (screenPixelRatio <= 1.8) {
      zoomLevel = "4";
    } else if (screenPixelRatio <= 1.9) {
      zoomLevel = "4.5";
    } else if (screenPixelRatio <= 2) {
      zoomLevel = "5";
    } else if (screenPixelRatio <= 2.1) {
      zoomLevel = "5.2";
    } else if (screenPixelRatio <= 2.2) {
      zoomLevel = "5.4";
    } else if (screenPixelRatio <= 2.3) {
      zoomLevel = "5.6";
    } else if (screenPixelRatio <= 2.4) {
      zoomLevel = "5.8";
    } else if (screenPixelRatio <= 2.5) {
      zoomLevel = "6";
    } else if (screenPixelRatio <= 2.6) {
      zoomLevel = "6.2";
    } else if (screenPixelRatio <= 2.7) {
      zoomLevel = "6.4";
    } else if (screenPixelRatio <= 2.8) {
      zoomLevel = "6.6";
    } else if (screenPixelRatio <= 2.9) {
      zoomLevel = "6.8";
    } else if (screenPixelRatio <= 3) {
      zoomLevel = "7";
    } else if (screenPixelRatio <= 3.1) {
      zoomLevel = "7.1";
    } else if (screenPixelRatio <= 3.2) {
      zoomLevel = "7.2";
    } else if (screenPixelRatio <= 3.3) {
      zoomLevel = "7.3";
    } else if (screenPixelRatio <= 3.4) {
      zoomLevel = "7.4";
    } else if (screenPixelRatio <= 3.5) {
      zoomLevel = "7.5";
    } else if (screenPixelRatio <= 3.6) {
      zoomLevel = "7.6";
    } else if (screenPixelRatio <= 3.7) {
      zoomLevel = "7.7";
    } else if (screenPixelRatio <= 3.8) {
      zoomLevel = "7.8";
    } else if (screenPixelRatio <= 3.9) {
      zoomLevel = "7.9";
    } else if (screenPixelRatio <= 4) {
      zoomLevel = "8";
    } else if (screenPixelRatio <= 4.1) {
      zoomLevel = "8.1";
    } else if (screenPixelRatio <= 4.2) {
      zoomLevel = "8.2";
    } else if (screenPixelRatio <= 4.3) {
      zoomLevel = "8.3";
    } else if (screenPixelRatio <= 4.4) {
      zoomLevel = "8.4";
    } else if (screenPixelRatio <= 4.5) {
      zoomLevel = "8.5";
    } else if (screenPixelRatio <= 4.6) {
      zoomLevel = "8.6";
    } else if (screenPixelRatio <= 4.7) {
      zoomLevel = "8.7";
    } else if (screenPixelRatio <= 4.8) {
      zoomLevel = "8.8";
    } else if (screenPixelRatio <= 4.9) {
      zoomLevel = "8.9";
    } else if (screenPixelRatio <= 5) {
      zoomLevel = "9";
    }else {
      zoomLevel = "unknown";
    }

    return zoomLevel;
};

在移动设备(Chrome for Android或Opera mobile)上,你可以通过window.visualViewport.scale来检测缩放。 https://developer.mozilla.org/en-US/docs/Web/API/Visual_Viewport_API

在Safari上检测:document.documentElement.clientWidth / window。innerWidth(如果设备上没有缩放则返回1)。

我的同事和我使用了来自https://github.com/tombigel/detect-zoom的脚本。此外,我们还动态地创建了一个svg元素并检查其currentScale属性。它在Chrome和大多数浏览器上都很好用。在FF上,“仅缩放文本”功能必须关闭。大多数浏览器都支持SVG。在撰写本文时,已在IE10、FF19和Chrome28上进行了测试。

var svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
svg.setAttribute('xmlns', 'http://www.w3.org/2000/svg');
svg.setAttribute('version', '1.1');
document.body.appendChild(svg);
var z = svg.currentScale;
... more code ...
document.body.removeChild(svg);

没有在IE中测试这个,但是如果你创建一个元素elem with

min-width: 100%

然后

window.document.width / elem.clientWidth

将为您提供浏览器缩放级别(包括document.body.style.zoom因子)。

我修复了下面的代码。

HTML:

<div class="mt-5"
        [ngStyle]="getStyles()">

TS:

getStyles() {
        const screenWidth = screen.width;
        const windowWidth = window.innerWidth;
        if (windowWidth != screenWidth) {
            const percentDifference = Math.ceil((screenWidth / windowWidth) * 100);
            if (percentDifference > 100) {
                this.bannerBackgroundImageSize = '20%, 74%';
            } else if (percentDifference === 100) {
                this.bannerBackgroundImageSize = '20%, 72%';
            } else if (percentDifference >= 90 && percentDifference <= 99) {
                this.bannerBackgroundImageSize = '25%, 70%';
            } else if (percentDifference >= 80 && percentDifference <= 89) {
                this.bannerBackgroundImageSize = '28%, 68%';
            } else if (percentDifference >= 75 && percentDifference <= 79) {
                this.bannerBackgroundImageSize = '29%, 67%';
            } else if (percentDifference >= 67 && percentDifference <= 74) {
                this.bannerBackgroundImageSize = '30%, 65%';
            } else if (percentDifference >= 50 && percentDifference <= 66) {
                this.bannerBackgroundImageSize = '30%, 61%';
            } else if (percentDifference < 50) {
                this.bannerBackgroundImageSize = '30%, 58%';
            }
        } else {
            this.bannerBackgroundImageSize = '20%, 72%';
        }
        const myStyles = {
            'background-size': this.bannerBackgroundImageSize,
        };
        return myStyles;
    }

我希望这将适用于所有缩放级别,它可以考虑与所有风格。