Markup Validation Service
Check the markup (HTML, XHTML, …) of Web documents
Markup Validation Service
Check the markup (HTML, XHTML, …) of Web documents
Line 67,
Column 9:
required attribute "TYPE" not specified
<style>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>.
Line 74,
Column 74:
NET-enabling start-tag requires SHORTTAG YES
<link rel="canonical" href="https://www.mersenne.org/report_exponent/" />
For the current document, the validator interprets strings like
<FOO /> according to legacy rules that
break the expectations of most authors and thus cause confusing warnings
and error messages from the validator. This interpretation is triggered
by HTML 4 documents or other SGML-based HTML documents. To avoid the
messages, simply remove the "/" character in such contexts. NB: If you
expect <FOO /> to be interpreted as an
XML-compatible "self-closing" tag, then you need to use XHTML or HTML5.
This warning and related errors may also be caused by an unquoted
attribute value containing one or more "/". Example:
<a href=http://w3c.org>W3C</a>.
In such cases, the solution is to put quotation marks around the value.
Line 75,
Column 7:
end tag for element "HEAD" which is not open
</head>The Validator found an end tag for the above element, but that element is not currently open. This is often caused by a leftover end tag from an element that was removed during editing, or by an implicitly closed element (if you have an error related to an element being used where it is not allowed, this is almost certainly the case). In the latter case this error will disappear as soon as you fix the original problem.
If this error occurred in a script section of your document, you should probably read this FAQ entry.
Line 76,
Column 6:
document type does not allow element "BODY" here
<body>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).
Line 77,
Column 10:
element "HEADER" undefined
<header>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:
Line 98,
Column 7:
element "NAV" undefined
<nav>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:
Line 179,
Column 22:
document type does not allow element "HR" here; missing one of "APPLET", "OBJECT", "MAP", "IFRAME", "BUTTON" start-tag
<li><span><hr></span></li>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>").
Line 198,
Column 11:
element "SECTION" undefined
<section>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:
Line 199,
Column 10:
element "MAIN" undefined
<main>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:
Line 202,
Column 13:
element "ARTICLE" undefined
<article>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:
Line 203,
Column 113:
value of attribute "TYPE" cannot be "NUMBER"; must be one of "TEXT", "PASSWORD", "CHECKBOX", "RADIO", "SUBMIT", "RESET", "FILE", "HIDDEN", "IMAGE", "BUTTON"
…/report_exponent/"><input type="number" min="2" max="999999999" name="exp_lo" …
The value of the attribute is defined to be one of a list of possible
values but in the document it contained something that is not allowed
for that type of attribute. For instance, the “selected” attribute must be either
minimized as “selected”
or spelled out in full as “selected="selected"”; a value like
“selected="true"” is not
allowed.
Line 203,
Column 119:
there is no attribute "MIN"
…t_exponent/"><input type="number" min="2" max="999999999" name="exp_lo" size="…You have used the attribute named above in your document, but the document type you are using does not support that attribute for this element. 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 "Transitional" document type to get the "target" attribute), or by using vendor proprietary extensions such as "marginheight" (this is usually fixed by using CSS to achieve the desired effect instead).
This error may also result if the element itself is not supported in the document type you are using, as an undefined element will have no supported attributes; in this case, see the element-undefined error message for further information.
How to fix: check the spelling and case of the element and attribute, (Remember XHTML is all lower-case) and/or check that they are both allowed in the chosen document type, and/or use CSS instead of this attribute. If you received this error when using the <embed> element to incorporate flash media in a Web page, see the FAQ item on valid flash.
Line 203,
Column 127:
there is no attribute "MAX"
…nt/"><input type="number" min="2" max="999999999" name="exp_lo" size="10" valu…You have used the attribute named above in your document, but the document type you are using does not support that attribute for this element. 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 "Transitional" document type to get the "target" attribute), or by using vendor proprietary extensions such as "marginheight" (this is usually fixed by using CSS to achieve the desired effect instead).
This error may also result if the element itself is not supported in the document type you are using, as an undefined element will have no supported attributes; in this case, see the element-undefined error message for further information.
How to fix: check the spelling and case of the element and attribute, (Remember XHTML is all lower-case) and/or check that they are both allowed in the chosen document type, and/or use CSS instead of this attribute. If you received this error when using the <embed> element to incorporate flash media in a Web page, see the FAQ item on valid flash.
Line 203,
Column 239:
value of attribute "TYPE" cannot be "NUMBER"; must be one of "TEXT", "PASSWORD", "CHECKBOX", "RADIO", "SUBMIT", "RESET", "FILE", "HIDDEN", "IMAGE", "BUTTON"
…ht; width:8em;"> to<input type="number" min="2" max="999999999" name="exp_hi" …
The value of the attribute is defined to be one of a list of possible
values but in the document it contained something that is not allowed
for that type of attribute. For instance, the “selected” attribute must be either
minimized as “selected”
or spelled out in full as “selected="selected"”; a value like
“selected="true"” is not
allowed.
Line 204,
Column 32:
document type does not allow element "TD" here; assuming missing "TR" start-tag
<td style="vertical-align:top;"><a target="_blank" style="color:black;" href="/…<td style="vertical-align:top;">History</td><td style="border:1px #999999 solid… <footer>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:
Line 223,
Column 15:
"ASYNC" is not a member of a group specified for any attribute
<script async type="text/javascript" src="//translate.google.com/translate_a/el…