Bonjour tout le monde, alors voilà j'ai quelques erreurs sur mes pages que je n'arrive pas à rectifier.  
 
Voici les principales:
 
1-# Error  Line 4 column 73: character data is not allowed here.
 
...e" content="text/html; charset=iso-8859-1" />
 
You have used character data somewhere it is not permitted to appear. Mistakes that can cause this error include putting text directly in the body of the document without wrapping it in a container element (such as a <p>aragraph</p> ) or forgetting to quote an attribute value (where characters such as "%" and "/" are common, but cannot appear without surrounding quotes).
 
✉
 
2-# Error  Line 14 column 42: required attribute "ALT" not specified.
 
  <img src="img/entete.jpg" usemap="#logo"/>
 
The attribute given above is required for an element that you've used, but you have omitted it. For instance, in most HTML and XHTML document types the "type" attribute is required on the "script" element and the "alt" attribute is required for the "img" element.
 
Typical values for type are type="text/css" for <style> and type="text/javascript" for <script>.
 
✉
 
3-Error  Line 20 column 45: required attribute "ALT" not specified.
 
  <img src="img/menu.jpg" usemap="#barremenu"/>
 
4-Error  Line 23 column 38: required attribute "ALT" not specified.
 
     href="index.html" title="Accueil">
 
merci

erreur 2:
ajouter alt="ent&ecirc;te"
erreur 3:
ajouter alt="menu"
erreur 4:
ajouter alt="retour accueil"
 
pour l erreur 1 il faudrait que tu files l adresse de ta page.

merci beaucoup, il ne me reste plus que deux erreurs:
 
la première:
 
Error  Line 6 column 116: non SGML character number 128.
 
.....d'1&#128;.....
 
You have used an illegal character in your text. HTML uses the standard UNICODE Consortium character repertoire, and it leaves undefined (among others) 65 character codes (0 to 31 inclusive and 127 to 159 inclusive) that are sometimes used for typographical quote marks and similar in proprietary character sets. The validator has found one of these undefined characters in your document. The character may appear on your browser as a curly quote, or a trademark symbol, or some other fancy glyph; on a different computer, however, it will likely appear as a completely different character, or nothing at all.
 
Your best bet is to replace the character with the nearest equivalent ASCII character, or to use an appropriate character entity. For more information on Character Encoding on the web, see Alan Flavell's excellent HTML Character Set Issues reference.
 
This error can also be triggered by formatting characters embedded in documents by some word processors. If you use a word processor to edit your HTML documents, be sure to use the "Save as ASCII" or similar command to save the document without formatting information.
 
L'apostrophe c'est bien &#39; non? Parce que lorsque je met ce code, il y'a une autre erreur sur le ;
 
et la seconde:
 
Error  Line 55 column 9: document type does not allow element "NOSCRIPT" here; missing one of "APPLET", "OBJECT", "MAP", "IFRAME", "BUTTON" start-tag.
 
</script>
<noscript>
   <img width="39" height="25" src="http://logv30.xiti.com/hit.xiti?s=247237&amp;p=" alt="Analyse d'audience" />
</noscript>
 
 
The mentioned element is not allowed to appear in the context in which you've placed it; the other mentioned elements are the only ones that are both allowed there and can contain the element mentioned. This might mean that you need a containing element, or possibly that you've forgotten to close a previous element.
 
One possible cause for this message is that you have attempted to put a block-level element (such as "<p>" or "<table>" ) inside an inline element (such as "<a>", "<span>", or "<font>" ).
 
 
encore merci

> L'apostrophe c'est bien &#39; non?
- non! c est ' (théoriquement &#39; mais dans la pratique pas supporté par tous les navigateurs)
> &#128;
- pire, pas unicode
 
l erreur <noscript> indique que tu n a pas la bonne version d HTML dans le header.
 
je peut pas te donner plus de précisions sans le code de ta page.