This is a very common XHTML mistake, now growing in visibility much due to the Google Chrome boom.
Google Chrome is based on Webkit, an open source browser engine also used in Apple’s Safari; Webkit is very restrict on XHTML rules;

This particular error is caused due to common HTML entities usage on XHTML outputs, which follows XML entities rules.
Basically means you are using a  -like entity, when in XHTML you should use a  -like entity;
The only named entities for XML are &, > and <. For all others you need to use the Unicode character code (eg.  ).

Here’s a HTML to XML entities conversion table:

Character HTML entity XML entity
" " "
& & &
< &lt; &#60;
> &gt; &#62;
  &nbsp; &#160;
¡ &iexcl; &#161;
¢ &cent; &#162;
£ &pound; &#163;
¤ &curren; &#164;
¥ &yen; &#165;
¦ &brvbar; &#166;
§ &sect; &#167;
¨ &uml; &#168;
© &copy; &#169;
ª &ordf; &#170;
« &laquo; &#171;
¬ &not; &#172;
­ &shy; &#173;
® &reg; &#174;
¯ &macr; &#175;
° &deg; &#176;
± &plusmn; &#177;
² &sup2; &#178;
³ &sup3; &#179;
´ &acute; &#180;
µ &micro; &#181;
&para; &#182;
· &middot; &#183;
¸ &cedil; &#184;
¹ &sup1; &#185;
º &ordm; &#186;
» &raquo; &#187;
¼ &frac14; &#188;
½ &frac12; &#189;
¾ &frac34; &#190;
¿ &iquest; &#191;
À &Agrave; &#192;
Á &Aacute; &#193;
 &Acirc; &#194;
à &Atilde; &#195;
Ä &Auml; &#196;
Å &Aring; &#197;
Æ &AElig; &#198;
Ç &Ccedil; &#199;
È &Egrave; &#200;
É &Eacute; &#201;
Ê &Ecirc; &#202;
Ë &Euml; &#203;
Ì &Igrave; &#204;
Í &Iacute; &#205;
Î &Icirc; &#206;
Ï &Iuml; &#207;
Ð &ETH; &#208;
Ñ &Ntilde; &#209;
Ò &Ograve; &#210;
Ó &Oacute; &#211;
Ô &Ocirc; &#212;
Õ &Otilde; &#213;
Ö &Ouml; &#214;
× &times; &#215;
Ø &Oslash; &#216;
Ù &Ugrave; &#217;
Ú &Uacute; &#218;
Û &Ucirc; &#219;
Ü &Uuml; &#220;
Ý &Yacute; &#221;
Þ &THORN; &#222;
ß &szlig; &#223;
à &agrave; &#224;
á &aacute; &#225;
â &acirc; &#226;
ã &atilde; &#227;
ä &auml; &#228;
å &aring; &#229;
æ &aelig; &#230;
ç &ccedil; &#231;
è &egrave; &#232;
é &eacute; &#233;
ê &ecirc; &#234;
ë &euml; &#235;
ì &igrave; &#236;
í &iacute; &#237;
î &icirc; &#238;
ï &iuml; &#239;
ð &eth; &#240;
ñ &ntilde; &#241;
ò &ograve; &#242;
ó &oacute; &#243;
ô &ocirc; &#244;
õ &otilde; &#245;
ö &ouml; &#246;
÷ &divide; &#247;
ø &oslash; &#248;
ù &ugrave; &#249;
ú &uacute; &#250;
û &ucirc; &#251;
ü &uuml; &#252;
ý &yacute; &#253;
þ &thorn; &#254;
ÿ &yuml; &#255;
€ &euro; &#8364;
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Posted in how-tos, xml | 6 Comments »

6 Responses

  1. benbois Says:
    November 19th, 2008 at 11:39 am

    thanks for the tips.. really useful.

  2. HiNuN Says:
    September 1st, 2009 at 2:39 pm

    “The only named entities for XML are &, > and <.”

    That’s wrong. There are five XML predefined entities:

    <, ", &, ' and >

  3. HiNuN Says:
    September 1st, 2009 at 2:40 pm

    “The only named entities for XML are &&, &> and &<.”

    That’s wrong. There are five XML predefined entities:

    &<, &", &&, &' and &>

  4. Jim D Says:
    October 29th, 2009 at 6:42 pm

    Maybe you’re reading a different spec than I am, but the   entity is clearly defined for XHTML – look at the spec.

    And if the doctype is in fact XHTML strict, they work fine in webkit.

    And if the doctype is HTML transitional, which you claim should work, then it fails in Webkit.

    Sorry, this is a webkit bug, pure and simple.

  5. Frans Says:
    February 13th, 2010 at 12:39 pm

    Jim D, in XHTML 5 there are no entities but the default XML ones. Of course, if Webkit has the same behavior in XHTML 1.0 and 1.1 then it’s a bug, but in XHTML 5 it’s not.

  6. Elemental Says:
    May 31st, 2010 at 12:47 pm

    Hello, i’m having trouble with webkit browsers (safari and chrome) displaying my web App.
    It shows this message “Entity ‘agrave’ not defined”.
    Do u have any idea how can i fix this? since it’s xhtml related

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