bonjour,
voila je débute dans le html et je viens de faire un teste sur w3c j'ai plusieurs erreurs dont je n'arrive pas a corriger :
Validation Output: 9 Errors

1. Error Line 24, Column 6: document type does not allow element "br" here; assuming missing "li" start-tag.

<br />

✉
2. Error Line 25, Column 4: document type does not allow element "li" here; missing one of "ul", "ol" start-tag.

<li><a href="http://tecs-chamberliere.ifrance.com/photo/photo.html">photo</a></

✉

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>").
3. Error Line 27, Column 4: document type does not allow element "li" here; missing one of "ul", "ol" start-tag.

<li><a href="http://tecs-chamberliere.ifrance.com/calendrier/calendrier.html">c

✉

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>").
4. Error Line 29, Column 4: document type does not allow element "li" here; missing one of "ul", "ol" start-tag.

<li><a href="http://tecs-chamberliere.ifrance.com/index.html">retour acceuil</a

✉

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>").
5. Error Line 30, Column 5: end tag for "li" omitted, but OMITTAG NO was specified.

</ul>

✉

You may have neglected to close an element, or perhaps you meant to "self-close" an element, that is, ending it with "/>" instead of ">".
6. Info Line 24, Column 1: start tag was here.

<br />

7. Error Line 42, Column 4: document type does not allow element "ol" here; missing one of "object", "ins", "del", "map", "button" start-tag.

<ol>

✉

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>").
8. Error Line 43, Column 4: document type does not allow element "ol" here; assuming missing "li" start-tag.

<ol>

✉
9. Error Line 48, Column 5: end tag for "li" omitted, but OMITTAG NO was specified.

</ol>

✉

You may have neglected to close an element, or perhaps you meant to "self-close" an element, that is, ending it with "/>" instead of ">".
10. Info Line 43, Column 1: start tag was here.

<ol>

11. Error Line 59, Column 6: document type does not allow element "br" here; missing one of "p", "h1", "h2", "h3", "h4", "h5", "h6", "div", "pre", "address", "fieldset", "ins", "del" start-tag.

<br />

✉

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>").