我无法让getBBox（）（或互联网上任何其他建议的方法）处理文本元素，所以我进入Chrome并构建了一个字符宽度查找表，然后console.将其登录到控制台，以便我可以将其复制到我的代码中，并使用它来查找文本中的字符。它很难看，而且没有考虑css的变化，但如果字体大小不变，它就能工作。
我在这里提供给那些没有其他途径获得信息的可怜人。
我是如何构建查找表的：

var clm= {}; // this is our dictionary
document.querySelector("#txt-add-title").addEventListener("keyup", function(e) {
 var bbox = document.querySelector("#measuring-stick").getBBox();
 var width = bbox.width;
 var target = e.currentTarget;
 var ch = target.value;
 if (!clm[ch]) {
     clm[ch] = width;
 }
});

现在-在 chrome -击中键盘上的每个字符一次，退格键后，每个所以你只测量一个字符，然后回去做Shift字符。这将在您的字典中注册每个键及其长度
完成后，在开发人员控制台中：

console.log(JSON.stringify(clm));

你会得到这样的东西：

{"0": 8.899147033691406, "1": 8.899147033691406, "2": 8.899147033691406, "3": 8.899147033691406, "4": 8.899147033691406,"5": 8.899147033691406, "6": 8.899147033691406, "7": 8.899147033691406, "8": 8.899147033691406, "9": 8.899147033691406, "a": 8.899147033691406, "": 0, "b": 8.899147033691406, "c": 8.181818008422852, "d": 8.899147033691406, "e": 8.899147033691406, "f": 5.454545021057129, "g": 8.899147033691406, "h": 8.899147033691406, "i": 3.5582385063171387, "j": 4.467329502105713, "k": 8.181818008422852, "l": 3.5582385063171387, "m": 13.330965042114258, "n": 8.899147033691406, "o": 8.899147033691406, "p": 8.899147033691406, "q": 8.899147033691406, "r": 5.909090518951416, "s": 8.004261016845703, "t": 4.545454502105713, "u": 8.899147033691406, "v": 8.181818008422852, "w": 12.272727012634277, "x": 8.63636302947998, "y": 8.181818008422852, "z": 8.181818008422852, "A": 11.363636016845703, "B": 10.674715995788574, "C": 11.555397033691406, "D": 11.555397033691406, "E": 10.674715995788574, "F": 9.779829025268555, "G": 12.450284004211426, "H": 11.555397033691406, "I": 4.4460225105285645, "J": 8.004261016845703, "K": 10.909090042114258, "L": 8.899147033691406, "M": 13.330965042114258, "N": 11.555397033691406, "O": 12.450284004211426, "P": 10.674715995788574, "Q": 12.450284004211426, "R": 11.818181037902832, "S": 10.674715995788574, "T": 9.779829025268555, "U": 11.555397033691406, "V": 11.363636016845703, "W": 15.106534004211426, "X": 11.363636016845703, "Y": 11.363636016845703, "Z": 9.779829025268555, "`": 5.33380651473999, "-": 5.33380651473999,"=": 9.346590995788574, "~": 9.346590995788574, "!": 4.4460225105285645, "@": 16.242897033691406, "#": 9.090909004211426, "$": 8.899147033691406, "%": 14.232954025268555, "^": 7.514204502105713, "&": 10.674715995788574, "*": 6.228693008422852, "(": 5.33380651473999, ")": 5.33380651473999, "_": 10, "+": 9.346590995788574, ",": 4.4460225105285645, "<": 9.346590995788574, ".": 4.4460225105285645, ">": 9.346590995788574, "/": 5, "?": 8.899147033691406, ":": 4.4460225105285645, ";": 4.4460225105285645,"'": 3.061079502105713, "[": 4.545454502105713, "{": 5.454545021057129, "]": 4.4460225105285645, "}": 5.348011016845703},

现在将其赋值给一个变量，每当你需要获取该文本节点的长度时，你只需获取值并循环字符以获取长度，就像这样：

var width = 0;
 var bbox = document.querySelector("#measuring-stick").getBBox();
if (bbox && bbox.width > 0) { // chrome works, yay!
                    width = bbox.width;
                } else { // mozilla needs the hack
                    var v= <get your element text here > ;
                    if (v.length > 0) {
                        for (let vp = 0; vp < v.length; vp++) {
                            width += mozCharLenLookup[v[vp]] || 0;
                        }
                    }
                }

这个解决方案让我有点抓狂，但它在字体大小不变的情况下是有效的，而且它们在两个浏览器中的大小大致相同。