How to convert characters to HTML entities using plain JavaScript
Solution 1:
With the help of bucabay and the advice to create my own function i created this one which works for me. What do you guys think, is there a better solution somewhere?
if(typeof escapeHtmlEntities == 'undefined') {
escapeHtmlEntities = function (text) {
return text.replace(/[\u00A0-\u2666<>\&]/g, function(c) {
return '&' +
(escapeHtmlEntities.entityTable[c.charCodeAt(0)] || '#'+c.charCodeAt(0)) + ';';
});
};
// all HTML4 entities as defined here: http://www.w3.org/TR/html4/sgml/entities.html
// added: amp, lt, gt, quot and apos
escapeHtmlEntities.entityTable = {
34 : 'quot',
38 : 'amp',
39 : 'apos',
60 : 'lt',
62 : 'gt',
160 : 'nbsp',
161 : 'iexcl',
162 : 'cent',
163 : 'pound',
164 : 'curren',
165 : 'yen',
166 : 'brvbar',
167 : 'sect',
168 : 'uml',
169 : 'copy',
170 : 'ordf',
171 : 'laquo',
172 : 'not',
173 : 'shy',
174 : 'reg',
175 : 'macr',
176 : 'deg',
177 : 'plusmn',
178 : 'sup2',
179 : 'sup3',
180 : 'acute',
181 : 'micro',
182 : 'para',
183 : 'middot',
184 : 'cedil',
185 : 'sup1',
186 : 'ordm',
187 : 'raquo',
188 : 'frac14',
189 : 'frac12',
190 : 'frac34',
191 : 'iquest',
192 : 'Agrave',
193 : 'Aacute',
194 : 'Acirc',
195 : 'Atilde',
196 : 'Auml',
197 : 'Aring',
198 : 'AElig',
199 : 'Ccedil',
200 : 'Egrave',
201 : 'Eacute',
202 : 'Ecirc',
203 : 'Euml',
204 : 'Igrave',
205 : 'Iacute',
206 : 'Icirc',
207 : 'Iuml',
208 : 'ETH',
209 : 'Ntilde',
210 : 'Ograve',
211 : 'Oacute',
212 : 'Ocirc',
213 : 'Otilde',
214 : 'Ouml',
215 : 'times',
216 : 'Oslash',
217 : 'Ugrave',
218 : 'Uacute',
219 : 'Ucirc',
220 : 'Uuml',
221 : 'Yacute',
222 : 'THORN',
223 : 'szlig',
224 : 'agrave',
225 : 'aacute',
226 : 'acirc',
227 : 'atilde',
228 : 'auml',
229 : 'aring',
230 : 'aelig',
231 : 'ccedil',
232 : 'egrave',
233 : 'eacute',
234 : 'ecirc',
235 : 'euml',
236 : 'igrave',
237 : 'iacute',
238 : 'icirc',
239 : 'iuml',
240 : 'eth',
241 : 'ntilde',
242 : 'ograve',
243 : 'oacute',
244 : 'ocirc',
245 : 'otilde',
246 : 'ouml',
247 : 'divide',
248 : 'oslash',
249 : 'ugrave',
250 : 'uacute',
251 : 'ucirc',
252 : 'uuml',
253 : 'yacute',
254 : 'thorn',
255 : 'yuml',
402 : 'fnof',
913 : 'Alpha',
914 : 'Beta',
915 : 'Gamma',
916 : 'Delta',
917 : 'Epsilon',
918 : 'Zeta',
919 : 'Eta',
920 : 'Theta',
921 : 'Iota',
922 : 'Kappa',
923 : 'Lambda',
924 : 'Mu',
925 : 'Nu',
926 : 'Xi',
927 : 'Omicron',
928 : 'Pi',
929 : 'Rho',
931 : 'Sigma',
932 : 'Tau',
933 : 'Upsilon',
934 : 'Phi',
935 : 'Chi',
936 : 'Psi',
937 : 'Omega',
945 : 'alpha',
946 : 'beta',
947 : 'gamma',
948 : 'delta',
949 : 'epsilon',
950 : 'zeta',
951 : 'eta',
952 : 'theta',
953 : 'iota',
954 : 'kappa',
955 : 'lambda',
956 : 'mu',
957 : 'nu',
958 : 'xi',
959 : 'omicron',
960 : 'pi',
961 : 'rho',
962 : 'sigmaf',
963 : 'sigma',
964 : 'tau',
965 : 'upsilon',
966 : 'phi',
967 : 'chi',
968 : 'psi',
969 : 'omega',
977 : 'thetasym',
978 : 'upsih',
982 : 'piv',
8226 : 'bull',
8230 : 'hellip',
8242 : 'prime',
8243 : 'Prime',
8254 : 'oline',
8260 : 'frasl',
8472 : 'weierp',
8465 : 'image',
8476 : 'real',
8482 : 'trade',
8501 : 'alefsym',
8592 : 'larr',
8593 : 'uarr',
8594 : 'rarr',
8595 : 'darr',
8596 : 'harr',
8629 : 'crarr',
8656 : 'lArr',
8657 : 'uArr',
8658 : 'rArr',
8659 : 'dArr',
8660 : 'hArr',
8704 : 'forall',
8706 : 'part',
8707 : 'exist',
8709 : 'empty',
8711 : 'nabla',
8712 : 'isin',
8713 : 'notin',
8715 : 'ni',
8719 : 'prod',
8721 : 'sum',
8722 : 'minus',
8727 : 'lowast',
8730 : 'radic',
8733 : 'prop',
8734 : 'infin',
8736 : 'ang',
8743 : 'and',
8744 : 'or',
8745 : 'cap',
8746 : 'cup',
8747 : 'int',
8756 : 'there4',
8764 : 'sim',
8773 : 'cong',
8776 : 'asymp',
8800 : 'ne',
8801 : 'equiv',
8804 : 'le',
8805 : 'ge',
8834 : 'sub',
8835 : 'sup',
8836 : 'nsub',
8838 : 'sube',
8839 : 'supe',
8853 : 'oplus',
8855 : 'otimes',
8869 : 'perp',
8901 : 'sdot',
8968 : 'lceil',
8969 : 'rceil',
8970 : 'lfloor',
8971 : 'rfloor',
9001 : 'lang',
9002 : 'rang',
9674 : 'loz',
9824 : 'spades',
9827 : 'clubs',
9829 : 'hearts',
9830 : 'diams',
338 : 'OElig',
339 : 'oelig',
352 : 'Scaron',
353 : 'scaron',
376 : 'Yuml',
710 : 'circ',
732 : 'tilde',
8194 : 'ensp',
8195 : 'emsp',
8201 : 'thinsp',
8204 : 'zwnj',
8205 : 'zwj',
8206 : 'lrm',
8207 : 'rlm',
8211 : 'ndash',
8212 : 'mdash',
8216 : 'lsquo',
8217 : 'rsquo',
8218 : 'sbquo',
8220 : 'ldquo',
8221 : 'rdquo',
8222 : 'bdquo',
8224 : 'dagger',
8225 : 'Dagger',
8240 : 'permil',
8249 : 'lsaquo',
8250 : 'rsaquo',
8364 : 'euro'
};
}
usage example:
var text = "Übergroße Äpfel mit Würmern";
alert(escapeHtmlEntities (text));
result:
Übergroße Äpfel mit Würmern
Update1: Thanks bucabay again for the || - hint
Update2: Updated entity table with amp,lt,gt,apos,quot, thanks richardtallent for the hint
Update3(in 2014): Mathias Bynens created a lib called 'he', maybe it serves your need.
Solution 2:
All the other solutions suggested here, as well as most other JavaScript libraries that do HTML entity encoding/decoding, make several mistakes:
- They don’t implement the full list of named character references that browsers support. For example,
htmlDecode('≼')should return'≼'(i.e.'\u227C'). - They don’t support encoding astral symbols correctly. For example,
htmlEncode('𝌆')should return something like𝌆or𝌆. If an implementation returns two separate entities instead (e.g.��or��), it is broken. - They don’t support decoding astral symbols correctly.
htmlDecode('𝌆')should return'𝌆'and not'팆'(i.e.'\uD306'). - They don’t implement the character reference overrides table listed in the HTML Standard. For example,
htmlDecode('€')should return'€'(i.e.'\u20AC'). - They should perform decoding in a single pass. For example,
htmlDecode('&amp;')should return'&', not&.
For a robust solution that avoids all these issues, use a library I wrote called he for this. From its README:
he (for “HTML entities”) is a robust HTML entity encoder/decoder written in JavaScript. It supports all standardized named character references as per HTML, handles ambiguous ampersands and other edge cases just like a browser would, has an extensive test suite, and — contrary to many other JavaScript solutions — he handles astral Unicode symbols just fine. An online demo is available.
Solution 3:
Using escape() should work with the character code range 0x00 to 0xFF (UTF-8 range).
If you go beyond 0xFF (255), such as 0x100 (256) then escape() will not work:
escape("\u0100"); // %u0100
and:
text = "\u0100"; // Ā
html = escape(text).replace(/%(..)/g,"&#x$1;"); // &#xu0;100
So, if you want to cover all Unicode charachacters as defined on http://www.w3.org/TR/html4/sgml/entities.html , then you could use something like:
var html = text.replace(/[\u00A0-\u00FF]/g, function(c) {
return '&#'+c.charCodeAt(0)+';';
});
Note here the range is between: \u00A0-\u00FF.
Thats the first character code range defined in http://www.w3.org/TR/html4/sgml/entities.html which is the same as what escape() covers.
You'll need to add the other ranges you want to cover as well, or all of them.
Example: UTF-8 range with general punctuations (\u00A0-\u00FF and \u2022-\u2135)
var html = text.replace(/[\u00A0-\u00FF\u2022-\u2135]/g, function(c) {
return '&#'+c.charCodeAt(0)+';';
});
Edit:
BTW: \u00A0-\u2666 should convert every Unicode character code not within ASCII range to HTML entities blindly:
var html = text.replace(/[\u00A0-\u2666]/g, function(c) {
return '&#'+c.charCodeAt(0)+';';
});
Solution 4:
You can use:
function encodeHTML(str){
var aStr = str.split(''),
i = aStr.length,
aRet = [];
while (i--) {
var iC = aStr[i].charCodeAt();
if (iC < 65 || iC > 127 || (iC>90 && iC<97)) {
aRet.push('&#'+iC+';');
} else {
aRet.push(aStr[i]);
}
}
return aRet.reverse().join('');
}
This function HTMLEncodes everything that is not a-z/A-Z.
[Edit] A rather old answer. Let's add a simpler String extension to encode all extended characters:
String.prototype.encodeHTML = function () {
return this.replace(/[\u0080-\u024F]/g,
function (v) {return '&#'+v.charCodeAt()+';';}
);
}
// usage
log('Übergroße Äpfel mit Würmern'.encodeHTML());
//=> 'Übergroße Äpfel mit Würmern'