Written by: Anne Holz | IANR MediaThis page will be continually updated as new common errors are found or reported.
Ampersands (&'s) in URLs
When writing a URL as text in HTML
&needs to be written as
Anchor element found with a valid href attribute, but no link content has been supplied.
An anchor tag must be around text or an image, the contents can not be blank.
<a href="">something must go in here</a>
Bad value "" for attribute "href" on element "a": Illegal character in path segment: not a URL code point.
Image names can not have spaces, replace spaces with %20.
Bad value _ for attribute _ on element _: Expected a digit but saw _ instead. Bad value “100%” for attribute “width” on element “iframe”: Expected a digit but saw “%” instead.
width="100%"from the iframe tag and add
style="width: 100%;"in the iframe tag.
Element “link” is missing required attribute “property”
Place <link> in the <head> instead of the <body>.
Element "style" is missing required attribute "scoped"
When using <style> in the body, add scoped to the style tag <style scoped>. It is preferred to place <style> in the <head> instead of the <body> when possible.
End tag for "body" seen, but there were unclosed elements
Most likely missing a closing div tag.
Heading tag found with no content.
An <h1>...<h6> tag must be around text, the contents can not be blank or contain something that isn't text, like an image.
<h2>text must go in here</h2>
Iframe element requires a non-empty title attribute that identifies the frame.
title="text describing iframe contents goes in here"inside the iframe tag.
No "p" element in scope but a "p" end tag seen.
Either a closing </p> tag is missing or the <p> tag contains a block element
The relationship between td elements and their associated th elements is not defined. Use either the scope attribute on th elements, or the headers attribute on td elements.
This error occurs when responsive table code is missing
headers="", which contains corresponding row and column id attributes, in the td tags.
This element has insufficient contrast at this conformance level. Expected a contrast ratio of at least 4.5:1
Text or background color is too light or dark. Use a color contrast tool to find values that pass WCAG 2 AA and AAA compliance.
The "frameborder" attribute on the "iframe" element is obsolete. Use CSS instead.
remove frameborder=0 from the iframe tag and in the CSS add