列出用户浏览器可以显示的每种字体

是的，有！我很高兴你问了这个问题，因为我现在也想使用它。

http://www.lalit.org/lab/javascript-css-font-detect

来自 http://www.lalit.org/wordpress/wp-content/uploads/2008/05/fontdetect.js?ver=0.3 的代码

/**
 * JavaScript code to detect available availability of a
 * particular font in a browser using JavaScript and CSS.
 *
 * Author : Lalit Patel
 * Website: http://www.lalit.org/lab/javascript-css-font-detect/
 * License: Apache Software License 2.0
 *          http://www.apache.org/licenses/LICENSE-2.0
 * Version: 0.15 (21 Sep 2009)
 *          Changed comparision font to default from sans-default-default,
 *          as in FF3.0 font of child element didn't fallback
 *          to parent element if the font is missing.
 * Version: 0.2 (04 Mar 2012)
 *          Comparing font against all the 3 generic font families ie,
 *          'monospace', 'sans-serif' and 'sans'. If it doesn't match all 3
 *          then that font is 100% not available in the system
 * Version: 0.3 (24 Mar 2012)
 *          Replaced sans with serif in the list of baseFonts
 */

/**
 * Usage: d = new Detector();
 *        d.detect('font name');
 */
var Detector = function() {
    // a font will be compared against all the three default fonts.
    // and if it doesn't match all 3 then that font is not available.
    var baseFonts = ['monospace', 'sans-serif', 'serif'];

    //we use m or w because these two characters take up the maximum width.
    // And we use a LLi so that the same matching fonts can get separated
    var testString = "mmmmmmmmmmlli";

    //we test using 72px font size, we may use any size. I guess larger the better.
    var testSize = '72px';

    var h = document.getElementsByTagName("body")[0];

    // create a SPAN in the document to get the width of the text we use to test
    var s = document.createElement("span");
    s.style.fontSize = testSize;
    s.innerHTML = testString;
    var defaultWidth = {};
    var defaultHeight = {};
    for (var index in baseFonts) {
        //get the default width for the three base fonts
        s.style.fontFamily = baseFonts[index];
        h.appendChild(s);
        defaultWidth[baseFonts[index]] = s.offsetWidth; //width for the default font
        defaultHeight[baseFonts[index]] = s.offsetHeight; //height for the defualt font
        h.removeChild(s);
    }

    function detect(font) {
        var detected = false;
        for (var index in baseFonts) {
            s.style.fontFamily = font + ',' + baseFonts[index]; // name of the font along with the base font for fallback.
            h.appendChild(s);
            var matched = (s.offsetWidth != defaultWidth[baseFonts[index]] || s.offsetHeight != defaultHeight[baseFonts[index]]);
            h.removeChild(s);
            detected = detected || matched;
        }
        return detected;
    }

    this.detect = detect;
};

总结

它是如何工作的？

此代码的工作原理很简单，即每个字符在不同的字体中以不同的方式显示。因此，对于相同字体大小的相同字符串，不同的字体将采用不同的宽度和高度。

JavaScript版本有点不可靠。它通过迭代已知字体和测试来获取字体。

最准确的方法（尽管必须使用专有插件）是使用Flash。在这里，您可以获得字体列表，而无需使用尺寸单独测试它们。

您将不得不决定是否以不在某些设备上工作（iDevices，没有Flash插件的浏览器等）为代价拥有确切的列表，还是仅通过JavaScript获得更好支持的部分列表。