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Mechanical accessibility check for the HTML. Please paste your HTML in the textarea of ​​HTML Source or enter target URL to URL in Check and send it. Display accessibility checkpoints and their commentary.

In the case of check by URL, in addition to checking accessibility, you can check images and alt.

Name of service

"A11yc Accessibility Check Service" Short version is "A11yc ACS"


Collected information


Technical information



If there is a request or correction part on the expression of the function, commentary, etc., please send us email (, Twitter, GitHub

Change Log

4.0.3 ()
Better Image List. Show text that exist with <img> in same <a> element.
4.0.2 ()
Fix Check Bug of alt of area. thx @yocco405
4.0.1 ()
Add mention of F16 to marquee. thx @yocco405
2.1.1 ()
Change service name.
Many Refactoring.
2.1.0 ()
start to support aria-label and aria-labelledby
2.0.9 ()
fix DOCTYPE recognition
better charset recognition
add images list mode by get request
2.0.8 ()
at html5, ignore check of existence of summary attribute
2.0.7 ()
no space between attribute.
better comment out logic.
ignore CDATA section.
2.0.6 ()
better <DOCTYPE> recognition.
2.0.5 ()
at readme: content of
at documentation: fix unexpectedlly escaped HTML and markup HTML by <code>.
at labelless check: if action attribute was not exists, use <form> to indicate place.
2.0.4 ()
Refine regular expression of extraction html tag.
Became able to check non UTF-8 page.
Update Japanese title of Techniques for WCAG 2.0.
Better lang check (#2).
2.0.3 ()
Add New check: fieldsetless and legendless.
Add link to Techniques for WCAG 2.0 into error message.
2.0.2 ()
Improve accuracy of getting attributes from html tag.
2.0.1 ()
Omit checking way of close of empty element.

Special Thanks