如何从字符串中删除重音字符? 特别是在IE6中,我有这样的东西:

accentsTidy = function(s){
    var r=s.toLowerCase();
    r = r.replace(new RegExp(/\s/g),"");
    r = r.replace(new RegExp(/[àáâãäå]/g),"a");
    r = r.replace(new RegExp(/æ/g),"ae");
    r = r.replace(new RegExp(/ç/g),"c");
    r = r.replace(new RegExp(/[èéêë]/g),"e");
    r = r.replace(new RegExp(/[ìíîï]/g),"i");
    r = r.replace(new RegExp(/ñ/g),"n");                
    r = r.replace(new RegExp(/[òóôõö]/g),"o");
    r = r.replace(new RegExp(/œ/g),"oe");
    r = r.replace(new RegExp(/[ùúûü]/g),"u");
    r = r.replace(new RegExp(/[ýÿ]/g),"y");
    r = r.replace(new RegExp(/\W/g),"");
    return r;
};

但是IE6让我很烦,它好像不喜欢我的正则表达式。


当前回答

我稍微修改了khel版本,原因之一是:每次regexp解析/替换将花费O(n)次操作,其中n是目标文本中的字符数。但是,regexp并不是我们所需要的。所以:

/* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ var defaultDiacriticsRemovalMap = [ {'base':'A', 'letters':'\u0041\u24B6\uFF21\u00C0\u00C1\u00C2\u1EA6\u1EA4\u1EAA\u1EA8\u00C3\u0100\u0102\u1EB0\u1EAE\u1EB4\u1EB2\u0226\u01E0\u00C4\u01DE\u1EA2\u00C5\u01FA\u01CD\u0200\u0202\u1EA0\u1EAC\u1EB6\u1E00\u0104\u023A\u2C6F'}, {'base':'AA','letters':'\uA732'}, {'base':'AE','letters':'\u00C6\u01FC\u01E2'}, {'base':'AO','letters':'\uA734'}, {'base':'AU','letters':'\uA736'}, {'base':'AV','letters':'\uA738\uA73A'}, {'base':'AY','letters':'\uA73C'}, {'base':'B', 'letters':'\u0042\u24B7\uFF22\u1E02\u1E04\u1E06\u0243\u0182\u0181'}, {'base':'C', 'letters':'\u0043\u24B8\uFF23\u0106\u0108\u010A\u010C\u00C7\u1E08\u0187\u023B\uA73E'}, {'base':'D', 'letters':'\u0044\u24B9\uFF24\u1E0A\u010E\u1E0C\u1E10\u1E12\u1E0E\u0110\u018B\u018A\u0189\uA779\u00D0'}, {'base':'DZ','letters':'\u01F1\u01C4'}, {'base':'Dz','letters':'\u01F2\u01C5'}, {'base':'E', 'letters':'\u0045\u24BA\uFF25\u00C8\u00C9\u00CA\u1EC0\u1EBE\u1EC4\u1EC2\u1EBC\u0112\u1E14\u1E16\u0114\u0116\u00CB\u1EBA\u011A\u0204\u0206\u1EB8\u1EC6\u0228\u1E1C\u0118\u1E18\u1E1A\u0190\u018E'}, {'base':'F', 'letters':'\u0046\u24BB\uFF26\u1E1E\u0191\uA77B'}, {'base':'G', 'letters':'\u0047\u24BC\uFF27\u01F4\u011C\u1E20\u011E\u0120\u01E6\u0122\u01E4\u0193\uA7A0\uA77D\uA77E'}, {'base':'H', 'letters':'\u0048\u24BD\uFF28\u0124\u1E22\u1E26\u021E\u1E24\u1E28\u1E2A\u0126\u2C67\u2C75\uA78D'}, {'base':'I', 'letters':'\u0049\u24BE\uFF29\u00CC\u00CD\u00CE\u0128\u012A\u012C\u0130\u00CF\u1E2E\u1EC8\u01CF\u0208\u020A\u1ECA\u012E\u1E2C\u0197'}, {'base':'J', 'letters':'\u004A\u24BF\uFF2A\u0134\u0248'}, {'base':'K', 'letters':'\u004B\u24C0\uFF2B\u1E30\u01E8\u1E32\u0136\u1E34\u0198\u2C69\uA740\uA742\uA744\uA7A2'}, {'base':'L', 'letters':'\u004C\u24C1\uFF2C\u013F\u0139\u013D\u1E36\u1E38\u013B\u1E3C\u1E3A\u0141\u023D\u2C62\u2C60\uA748\uA746\uA780'}, {'base':'LJ','letters':'\u01C7'}, {'base':'Lj','letters':'\u01C8'}, {'base':'M', 'letters':'\u004D\u24C2\uFF2D\u1E3E\u1E40\u1E42\u2C6E\u019C'}, {'base':'N', 'letters':'\u004E\u24C3\uFF2E\u01F8\u0143\u00D1\u1E44\u0147\u1E46\u0145\u1E4A\u1E48\u0220\u019D\uA790\uA7A4'}, {'base':'NJ','letters':'\u01CA'}, {'base':'Nj','letters':'\u01CB'}, {'base':'O', 'letters':'\u004F\u24C4\uFF2F\u00D2\u00D3\u00D4\u1ED2\u1ED0\u1ED6\u1ED4\u00D5\u1E4C\u022C\u1E4E\u014C\u1E50\u1E52\u014E\u022E\u0230\u00D6\u022A\u1ECE\u0150\u01D1\u020C\u020E\u01A0\u1EDC\u1EDA\u1EE0\u1EDE\u1EE2\u1ECC\u1ED8\u01EA\u01EC\u00D8\u01FE\u0186\u019F\uA74A\uA74C'}, {'base':'OI','letters':'\u01A2'}, {'base':'OO','letters':'\uA74E'}, {'base':'OU','letters':'\u0222'}, {'base':'OE','letters':'\u008C\u0152'}, {'base':'oe','letters':'\u009C\u0153'}, {'base':'P', 'letters':'\u0050\u24C5\uFF30\u1E54\u1E56\u01A4\u2C63\uA750\uA752\uA754'}, {'base':'Q', 'letters':'\u0051\u24C6\uFF31\uA756\uA758\u024A'}, {'base':'R', 'letters':'\u0052\u24C7\uFF32\u0154\u1E58\u0158\u0210\u0212\u1E5A\u1E5C\u0156\u1E5E\u024C\u2C64\uA75A\uA7A6\uA782'}, {'base':'S', 'letters':'\u0053\u24C8\uFF33\u1E9E\u015A\u1E64\u015C\u1E60\u0160\u1E66\u1E62\u1E68\u0218\u015E\u2C7E\uA7A8\uA784'}, {'base':'T', 'letters':'\u0054\u24C9\uFF34\u1E6A\u0164\u1E6C\u021A\u0162\u1E70\u1E6E\u0166\u01AC\u01AE\u023E\uA786'}, {'base':'TZ','letters':'\uA728'}, {'base':'U', 'letters':'\u0055\u24CA\uFF35\u00D9\u00DA\u00DB\u0168\u1E78\u016A\u1E7A\u016C\u00DC\u01DB\u01D7\u01D5\u01D9\u1EE6\u016E\u0170\u01D3\u0214\u0216\u01AF\u1EEA\u1EE8\u1EEE\u1EEC\u1EF0\u1EE4\u1E72\u0172\u1E76\u1E74\u0244'}, {'base':'V', 'letters':'\u0056\u24CB\uFF36\u1E7C\u1E7E\u01B2\uA75E\u0245'}, {'base':'VY','letters':'\uA760'}, {'base':'W', 'letters':'\u0057\u24CC\uFF37\u1E80\u1E82\u0174\u1E86\u1E84\u1E88\u2C72'}, {'base':'X', 'letters':'\u0058\u24CD\uFF38\u1E8A\u1E8C'}, {'base':'Y', 'letters':'\u0059\u24CE\uFF39\u1EF2\u00DD\u0176\u1EF8\u0232\u1E8E\u0178\u1EF6\u1EF4\u01B3\u024E\u1EFE'}, {'base':'Z', 'letters':'\u005A\u24CF\uFF3A\u0179\u1E90\u017B\u017D\u1E92\u1E94\u01B5\u0224\u2C7F\u2C6B\uA762'}, {'base':'a', 'letters':'\u0061\u24D0\uFF41\u1E9A\u00E0\u00E1\u00E2\u1EA7\u1EA5\u1EAB\u1EA9\u00E3\u0101\u0103\u1EB1\u1EAF\u1EB5\u1EB3\u0227\u01E1\u00E4\u01DF\u1EA3\u00E5\u01FB\u01CE\u0201\u0203\u1EA1\u1EAD\u1EB7\u1E01\u0105\u2C65\u0250'}, {'base':'aa','letters':'\uA733'}, {'base':'ae','letters':'\u00E6\u01FD\u01E3'}, {'base':'ao','letters':'\uA735'}, {'base':'au','letters':'\uA737'}, {'base':'av','letters':'\uA739\uA73B'}, {'base':'ay','letters':'\uA73D'}, {'base':'b', 'letters':'\u0062\u24D1\uFF42\u1E03\u1E05\u1E07\u0180\u0183\u0253'}, {'base':'c', 'letters':'\u0063\u24D2\uFF43\u0107\u0109\u010B\u010D\u00E7\u1E09\u0188\u023C\uA73F\u2184'}, {'base':'d', 'letters':'\u0064\u24D3\uFF44\u1E0B\u010F\u1E0D\u1E11\u1E13\u1E0F\u0111\u018C\u0256\u0257\uA77A'}, {'base':'dz','letters':'\u01F3\u01C6'}, {'base':'e', 'letters':'\u0065\u24D4\uFF45\u00E8\u00E9\u00EA\u1EC1\u1EBF\u1EC5\u1EC3\u1EBD\u0113\u1E15\u1E17\u0115\u0117\u00EB\u1EBB\u011B\u0205\u0207\u1EB9\u1EC7\u0229\u1E1D\u0119\u1E19\u1E1B\u0247\u025B\u01DD'}, {'base':'f', 'letters':'\u0066\u24D5\uFF46\u1E1F\u0192\uA77C'}, {'base':'g', 'letters':'\u0067\u24D6\uFF47\u01F5\u011D\u1E21\u011F\u0121\u01E7\u0123\u01E5\u0260\uA7A1\u1D79\uA77F'}, {'base':'h', 'letters':'\u0068\u24D7\uFF48\u0125\u1E23\u1E27\u021F\u1E25\u1E29\u1E2B\u1E96\u0127\u2C68\u2C76\u0265'}, {'base':'hv','letters':'\u0195'}, {'base':'i', 'letters':'\u0069\u24D8\uFF49\u00EC\u00ED\u00EE\u0129\u012B\u012D\u00EF\u1E2F\u1EC9\u01D0\u0209\u020B\u1ECB\u012F\u1E2D\u0268\u0131'}, {'base':'j', 'letters':'\u006A\u24D9\uFF4A\u0135\u01F0\u0249'}, {'base':'k', 'letters':'\u006B\u24DA\uFF4B\u1E31\u01E9\u1E33\u0137\u1E35\u0199\u2C6A\uA741\uA743\uA745\uA7A3'}, {'base':'l', 'letters':'\u006C\u24DB\uFF4C\u0140\u013A\u013E\u1E37\u1E39\u013C\u1E3D\u1E3B\u017F\u0142\u019A\u026B\u2C61\uA749\uA781\uA747'}, {'base':'lj','letters':'\u01C9'}, {'base':'m', 'letters':'\u006D\u24DC\uFF4D\u1E3F\u1E41\u1E43\u0271\u026F'}, {'base':'n', 'letters':'\u006E\u24DD\uFF4E\u01F9\u0144\u00F1\u1E45\u0148\u1E47\u0146\u1E4B\u1E49\u019E\u0272\u0149\uA791\uA7A5'}, {'base':'nj','letters':'\u01CC'}, {'base':'o', 'letters':'\u006F\u24DE\uFF4F\u00F2\u00F3\u00F4\u1ED3\u1ED1\u1ED7\u1ED5\u00F5\u1E4D\u022D\u1E4F\u014D\u1E51\u1E53\u014F\u022F\u0231\u00F6\u022B\u1ECF\u0151\u01D2\u020D\u020F\u01A1\u1EDD\u1EDB\u1EE1\u1EDF\u1EE3\u1ECD\u1ED9\u01EB\u01ED\u00F8\u01FF\u0254\uA74B\uA74D\u0275'}, {'base':'oi','letters':'\u01A3'}, {'base':'ou','letters':'\u0223'}, {'base':'oo','letters':'\uA74F'}, {'base':'p','letters':'\u0070\u24DF\uFF50\u1E55\u1E57\u01A5\u1D7D\uA751\uA753\uA755'}, {'base':'q','letters':'\u0071\u24E0\uFF51\u024B\uA757\uA759'}, {'base':'r','letters':'\u0072\u24E1\uFF52\u0155\u1E59\u0159\u0211\u0213\u1E5B\u1E5D\u0157\u1E5F\u024D\u027D\uA75B\uA7A7\uA783'}, {'base':'s','letters':'\u0073\u24E2\uFF53\u00DF\u015B\u1E65\u015D\u1E61\u0161\u1E67\u1E63\u1E69\u0219\u015F\u023F\uA7A9\uA785\u1E9B'}, {'base':'t','letters':'\u0074\u24E3\uFF54\u1E6B\u1E97\u0165\u1E6D\u021B\u0163\u1E71\u1E6F\u0167\u01AD\u0288\u2C66\uA787'}, {'base':'tz','letters':'\uA729'}, {'base':'u','letters': '\u0075\u24E4\uFF55\u00F9\u00FA\u00FB\u0169\u1E79\u016B\u1E7B\u016D\u00FC\u01DC\u01D8\u01D6\u01DA\u1EE7\u016F\u0171\u01D4\u0215\u0217\u01B0\u1EEB\u1EE9\u1EEF\u1EED\u1EF1\u1EE5\u1E73\u0173\u1E77\u1E75\u0289'}, {'base':'v','letters':'\u0076\u24E5\uFF56\u1E7D\u1E7F\u028B\uA75F\u028C'}, {'base':'vy','letters':'\uA761'}, {'base':'w','letters':'\u0077\u24E6\uFF57\u1E81\u1E83\u0175\u1E87\u1E85\u1E98\u1E89\u2C73'}, {'base':'x','letters':'\u0078\u24E7\uFF58\u1E8B\u1E8D'}, {'base':'y','letters':'\u0079\u24E8\uFF59\u1EF3\u00FD\u0177\u1EF9\u0233\u1E8F\u00FF\u1EF7\u1E99\u1EF5\u01B4\u024F\u1EFF'}, {'base':'z','letters':'\u007A\u24E9\uFF5A\u017A\u1E91\u017C\u017E\u1E93\u1E95\u01B6\u0225\u0240\u2C6C\uA763'} ]; var diacriticsMap = {}; for (var i=0; i < defaultDiacriticsRemovalMap .length; i++){ var letters = defaultDiacriticsRemovalMap [i].letters; for (var j=0; j < letters.length ; j++){ diacriticsMap[letters[j]] = defaultDiacriticsRemovalMap [i].base; } } // "what?" version ... http://jsperf.com/diacritics/12 function removeDiacritics (str) { return str.replace(/[^\u0000-\u007E]/g, function(a){ return diacriticsMap[a] || a; }); } var paragraph = "L'avantage d'utiliser le lorem ipsum est bien évidemment de pouvoir créer des maquettes ou de remplir un site internet de contenus qui présentent un rendu s'approchant un maximum du rendu final. \n Par défaut lorem ipsum ne contient pas d'accent ni de caractères spéciaux contrairement à la langue française qui en contient beaucoup. C'est sur ce critère que nous proposons une solution avec cet outil qui générant du faux-texte lorem ipsum mais avec en plus, des caractères spéciaux tel que les accents ou certains symboles utiles pour la langue française. \n L'utilisation du lorem standard est facile d’utilisation mais lorsque le futur client utilisera votre logiciel il se peut que certains caractères spéciaux ou qu'un accent ne soient pas codés correctement. \n Cette page a pour but donc de pouvoir perdre le moins de temps possible et donc de tester directement si tous les encodages de base de donnée ou des sites sont les bons de plus il permet de récuperer un code css avec le texte formaté !"; alert(removeDiacritics(paragraph));

为了验证我的理论,我在http://jsperf.com/diacritics/12上写了一个测试。结果:

在Windows 8 64位的Chrome 28.0.1500.95 32位的测试: 使用正则表达式 4558 ops/sec±4.16%。慢37% 字符串生成器样式 7308次/秒±4.88%。最快

更新

在Windows 8 64位的Chrome 33.0.1750测试:

使用正则表达式 5260±1.25% ops/sec,慢76% 使用@skerit版本 22138±2.12% ops/sec最快

更新日期:2014年3月19日

增加丢失的“OE”变音符。

更新日期:2014年3月27日

使用一个更快的方法横向字符串使用js - "什么?"版本

更新日期:2014年5月14日

社区维基

其他回答

将一个用户定义的函数传递给Array.sort()方法,并在这个用户定义的函数中使用String.localeCompare()

function myCompareFunction(a, b) {
  return a.localeCompare(b);
}

var values = ["pêches", "épinards", "tomates", "fraises"];

// WRONG: ["fraises", "pêches", "tomates", "épinards"]
values.sort();

 // **GOOD**: ["épinards", "fraises", "pêches", "tomates"]
values.sort(myCompareFunction);

新RegExp的格式为

RegExp(something, 'modifiers');

所以你会想

accentsTidy = function(s){
                        var r=s.toLowerCase();
                        r = r.replace(new RegExp("\\s", 'g'),"");
                        r = r.replace(new RegExp("[àáâãäå]", 'g'),"a");
                        r = r.replace(new RegExp("æ", 'g'),"ae");
                        r = r.replace(new RegExp("ç", 'g'),"c");
                        r = r.replace(new RegExp("[èéêë]", 'g'),"e");
                        r = r.replace(new RegExp("[ìíîï]", 'g'),"i");
                        r = r.replace(new RegExp("ñ", 'g'),"n");                            
                        r = r.replace(new RegExp("[òóôõö]", 'g'),"o");
                        r = r.replace(new RegExp("œ", 'g'),"oe");
                        r = r.replace(new RegExp("[ùúûü]", 'g'),"u");
                        r = r.replace(new RegExp("[ýÿ]", 'g'),"y");
                        r = r.replace(new RegExp("\\W", 'g'),"");
                        return r;
                };

有很多这样的方法,但我认为这个方法简单且足够好:

 function remove_accents(strAccents) {
    var strAccents = strAccents.split('');
    var strAccentsOut = new Array();
    var strAccentsLen = strAccents.length;
    var accents =    "ÀÁÂÃÄÅàáâãäåÒÓÔÕÕÖØòóôõöøÈÉÊËèéêëÇçðÐÌÍÎÏìíîïÙÚÛÜùúûüÑñŠšŸÿýŽž";
    var accentsOut = "AAAAAAaaaaaaOOOOOOOooooooEEEEeeeeCcdDIIIIiiiiUUUUuuuuNnSsYyyZz";
    for (var y = 0; y < strAccentsLen; y++) {
        if (accents.indexOf(strAccents[y]) != -1) {
            strAccentsOut[y] = accentsOut.substr(accents.indexOf(strAccents[y]), 1);
        } else
            strAccentsOut[y] = strAccents[y];
    }
    strAccentsOut = strAccentsOut.join('');

    return strAccentsOut;
}

如果你还想删除特殊字符,并转换下划线中的空格和连字符,请执行以下操作:

string = remove_accents(string);
string = string.replace(/[^a-z0-9\s]/gi, '').replace(/[-\s]/g, '_');

使用ES2015/ES6 String.prototype.normalize(),

const str = "Crème Brulée"
str.normalize("NFD").replace(/[\u0300-\u036f]/g, "")
> "Creme Brulee"

注意:如果你想让\uFB01(fi)标准化(到fi),请使用NFKD。

这里发生了两件事:

Unicode标准格式将组合的字形分解为简单字形的组合。Crème的è最后表示为e + +。 使用正则表达式字符类来匹配U+0300→U+036F范围,现在可以很容易地全局消除变音符,Unicode标准将其方便地分组为组合变音符标记Unicode块。

从2021年开始,还可以使用Unicode属性转义:

str.normalize("NFD").replace(/\p{Diacritic}/gu, "")

有关性能测试,请参阅注释。

或者,如果你只是想排序

Intl。Collator有足够的支持~95%现在,polyfill也可以在这里,但我还没有测试它。

const c = new Intl.Collator();
["creme brulee", "crème brulée", "crame brulai", "crome brouillé",
"creme brulay", "creme brulfé", "creme bruléa"].sort(c.compare)
["crame brulai", "creme brulay", "creme bruléa", "creme brulee",
"crème brulée", "creme brulfé", "crome brouillé"]


["creme brulee", "crème brulée", "crame brulai", "crome brouillé"].sort((a,b) => a>b)
["crame brulai", "creme brulee", "crome brouillé", "crème brulée"]

谢谢大家 我使用这个版本并说明原因(因为我在开始时错过了这些解释,所以我试图帮助下一个读者,如果他和我一样无聊…)

备注:我想要一个高效的解决方案,所以:

只有一次regexp编译(如果需要) 每个字符串只扫描一个字符串 查找已翻译字符的有效方法 等等……

我的版本是: (里面没有新的技术技巧,只有一些精选的+解释)

makeSortString = (function() {
    var translate_re = /[¹²³áàâãäåaaaÀÁÂÃÄÅAAAÆccç©CCÇÐÐèéê?ëeeeeeÈÊË?EEEEE€gGiìíîïìiiiÌÍÎÏ?ÌIIIlLnnñNNÑòóôõöoooøÒÓÔÕÖOOOØŒr®Ršs?ߊS?ùúûüuuuuÙÚÛÜUUUUýÿÝŸžzzŽZZ]/g;
    var translate = {
"¹":"1","²":"2","³":"3","á":"a","à":"a","â":"a","ã":"a","ä":"a","å":"a","a":"a","a":"a","a":"a","À":"a","Á":"a","Â":"a","Ã":"a","Ä":"a","Å":"a","A":"a","A":"a",
"A":"a","Æ":"a","c":"c","c":"c","ç":"c","©":"c","C":"c","C":"c","Ç":"c","Ð":"d","Ð":"d","è":"e","é":"e","ê":"e","?":"e","ë":"e","e":"e","e":"e","e":"e","e":"e",
"e":"e","È":"e","Ê":"e","Ë":"e","?":"e","E":"e","E":"e","E":"e","E":"e","E":"e","€":"e","g":"g","G":"g","i":"i","ì":"i","í":"i","î":"i","ï":"i","ì":"i","i":"i",
"i":"i","i":"i","Ì":"i","Í":"i","Î":"i","Ï":"i","?":"i","Ì":"i","I":"i","I":"i","I":"i","l":"l","L":"l","n":"n","n":"n","ñ":"n","N":"n","N":"n","Ñ":"n","ò":"o",
"ó":"o","ô":"o","õ":"o","ö":"o","o":"o","o":"o","o":"o","ø":"o","Ò":"o","Ó":"o","Ô":"o","Õ":"o","Ö":"o","O":"o","O":"o","O":"o","Ø":"o","Œ":"o","r":"r","®":"r",
"R":"r","š":"s","s":"s","?":"s","ß":"s","Š":"s","S":"s","?":"s","ù":"u","ú":"u","û":"u","ü":"u","u":"u","u":"u","u":"u","u":"u","Ù":"u","Ú":"u","Û":"u","Ü":"u",
"U":"u","U":"u","U":"u","U":"u","ý":"y","ÿ":"y","Ý":"y","Ÿ":"y","ž":"z","z":"z","z":"z","Ž":"z","Z":"z","Z":"z"
    };
    return function(s) {
        return(s.replace(translate_re, function(match){return translate[match];}) );
    }
})();

我是这样用的:

var without_accents = makeSortString("wïthêüÄTrèsBïgüeAk100t");
// I let you guess the result,
// no I was kidding you : I give you the result : witheuatresbigueak100t

评论:

Tthe instruction inside it is done once (after, makeSortString != undefined) function(){...} is stored once in makeSortString, so the "big" translate_re and translate objects are stored once When you call makeSortString('something') it call directly the inside function which calls only s.replace(...) : it is efficient s.replace uses regexp (the special syntax of var translate_re= .... is in fact equivalent to var translate_re = new RegExp("[¹....Z]","g"); but the compilation of the regexp is done once for all, and the scan of the s String is done one for a call of the function (not for every character as it would be in a loop) For each character found s.replace calls function(match) where parameter match contains the character found, and it call the corresponding translated character (translate[match]) Translate[match] is probably efficient too as the javascript translate object is probably implemented by javascript with a hashtab or something equivalent and allow the program to find the translated character almost directly and not for instance through a loop on a array of all characters to find the right one (which would be awfully unefficient).