zoom = ( window.outerWidth - 10 ) / window.innerWidth

这就是你所需要的。

一个变通的FireFox 16+找到DPPX(缩放级别)纯粹与JavaScript:

var dppx = (function (precision) {
  var searchDPPX = function(level, min, divisor) {
    var wmq = window.matchMedia;
    while (level >= min && !wmq("(min-resolution: " + (level/divisor) + "dppx)").matches) {
      level--;
    }
    return level;
  };

  var maxDPPX = 5.0; // Firefox 22 has 3.0 as maximum, but testing a bit greater values does not cost much
  var minDPPX = 0.1; // Firefox 22 has 0.3 as minimum, but testing a bit smaller values does not cost anything
  var divisor = 1;
  var result;
  for (var i = 0; i < precision; i++) {
    result = 10 * searchDPPX (maxDPPX, minDPPX, divisor);
    maxDPPX = result + 9;
    minDPPX = result;
    divisor *= 10;
  }

  return result / divisor;
}) (5);

基本上，我们有:

devicepixelratio，它同时考虑了浏览器级别的缩放*以及系统缩放/像素密度。 *在Mac/Safari上不考虑缩放级别 媒体查询 vw/vh CSS单位 缩放级别更改时触发的Resize事件，会导致窗口的有效大小更改

这对于正常的用户体验来说应该足够了。如果你需要检测缩放级别，这可能是糟糕UI设计的标志。

音高变焦更难跟踪，目前还没有考虑。

这是一个很久以前发布的问题，但今天当我在寻找相同的答案“如何检测放大和缩小事件”时，我找不到一个适合所有浏览器的答案。

就像现在一样:对于Firefox/Chrome/IE8和IE9，放大和缩小会触发一个窗口。调整大小事件。 可以使用以下方法捕获:

$(window).resize(function() {
//YOUR CODE.
});

这可能会或可能不会帮助任何人，但我有一个页面，我不能得到正确的中心，无论什么Css技巧我尝试了，所以我写了一个JQuery文件呼叫中心页面:

问题发生在浏览器的缩放级别，页面会根据您的100%，125%，150%等进行移动。

下面的代码位于一个名为centerpage.js的JQuery文件中。

从我的页面，我必须链接到JQuery和这个文件才能让它工作，即使我的主页已经有一个链接到JQuery。

<title>Home Page.</title>
<script src="Scripts/jquery-1.7.1.min.js"></script>
<script src="Scripts/centerpage.js"></script>

centerpage.js:

// centering page element
function centerPage() {
    // get body element
    var body = document.body;

    // if the body element exists
    if (body != null) {
        // get the clientWidth
        var clientWidth = body.clientWidth;

        // request data for centering
        var windowWidth = document.documentElement.clientWidth;
        var left = (windowWidth - bodyWidth) / 2;

        // this is a hack, but it works for me a better method is to determine the 
        // scale but for now it works for my needs
        if (left > 84) {
            // the zoom level is most likely around 150 or higher
            $('#MainBody').removeClass('body').addClass('body150');
        } else if (left < 100) {
            // the zoom level is most likely around 110 - 140
            $('#MainBody').removeClass('body').addClass('body125');
        }
    }
}


// CONTROLLING EVENTS IN jQuery
$(document).ready(function() {
    // center the page
    centerPage();
});

如果你想让一个面板居中:

// centering panel
function centerPanel($panelControl) {
    // if the panel control exists
    if ($panelControl && $panelControl.length) {
        // request data for centering
        var windowWidth = document.documentElement.clientWidth;
        var windowHeight = document.documentElement.clientHeight;
        var panelHeight = $panelControl.height();
        var panelWidth = $panelControl.width();

        // centering
        $panelControl.css({
            'position': 'absolute',
            'top': (windowHeight - panelHeight) / 2,
            'left': (windowWidth - panelWidth) / 2
        });

        // only need force for IE6
        $('#backgroundPanel').css('height', windowHeight);
    }
}

I found this article enormously helpful. Huge thanks to yonran. I wanted to pass on some additional learning I found while implementing some of the techniques he provided. In FF6 and Chrome 9, support for media queries from JS was added, which can greatly simplify the media query approach necessary for determining zoom in FF. See the docs at MDN here. For my purposes, I only needed to detect whether the browser was zoomed in or out, I had no need for the actual zoom factor. I was able to get my answer with one line of JavaScript:

var isZoomed = window.matchMedia('(max--moz-device-pixel-ratio:0.99), (min--moz-device-pixel-ratio:1.01)').matches;

结合IE8+和Webkit解决方案(它们也是单行的)，我能够在只有几行代码的情况下检测到绝大多数浏览器的缩放效果。