Errors Founded :
Line 3, Column 74: document type does not allow element "meta" here
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
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The element named above was found in a context where it is not allowed. This could mean that you have incorrectly nested elements -- such as a "style" element in the "body" section instead of inside "head" -- or two elements that overlap (which is not allowed).
One common cause for this error is the use of XHTML syntax in HTML documents. Due to HTML's rules of implicitly closed elements, this error can create cascading effects. For instance, using XHTML's "self-closing" tags for "meta" and "link" in the "head" section of a HTML document may cause the parser to infer the end of the "head" section and the beginning of the "body" section (where "link" and "meta" are not allowed; hence the reported error).
Error Line 4, Column 1: Missing xmlns attribute for element html. The value should be: http://www.w3.org/1999/xhtml
<html>
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Many Document Types based on XML need a mandatory xmlns attribute on the root element. For example, the root element for XHTML might look like:
<html xmlns="http://www.w3.org/1999/xhtml">
Error Line 8, Column 7: element "BODY" undefined
<BODY>
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You have used the element named above in your document, but the document type you are using does not define an element of that name. This error is often caused by:
incorrect use of the "Strict" document type with a document that uses frames (e.g. you must use the "Frameset" document type to get the "<frameset>" element),
by using vendor proprietary extensions such as "<spacer>" or "<marquee>" (this is usually fixed by using CSS to achieve the desired effect instead).
by using upper-case tags in XHTML (in XHTML attributes and elements must be all lower-case).
Error Line 20, Column 7: end tag for "html" which is not finished
</html>
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Most likely, you nested tags and closed them in the wrong order. For example <p><em>...</p> is not acceptable, as <em> must be closed before <p>. Acceptable nesting is: <p><em>...</em></p>
Another possibility is that you used an element which requires a child element that you did not include. Hence the parent element is "not finished", not complete. For instance, in HTML the <head> element must contain a <title> child element, lists require appropriate list items (<ul> and <ol> require <li>; <dl> requires <dt> and <dd>), and so on.