- From: WCAG 2.0 Techniques Submission Form <nobody@w3.org>
- Date: Wed, 4 Jun 2008 16:57:10 +0000 (GMT)
- To: public-wcag2-techs@w3.org
Submitter's Name: Laura Carlson Submitter's Email: laura.lee.carlson@gmail.com Technique ID: UNKNOWN Short Name: Providing Text Alternatives for CAPTCHA Images. Technique Category: HTML and XHTML Techniques Guideline Reference: text-equiv Success Criterion Reference: UNKNOWN Applicability: Applies to HTML UA Issues: None known Description: The objective of this technique is explain and demonstrate how to markup CAPTCHA Images. CAPTCHA stands for "Completely Automated Public Turing test to tell Computers and Humans Apart". CAPTCHA images are used for security purposes to confirm that content is being accessed by a person rather than a computer. This authentication is done through visual verification of an image. CAPTCHA typically presents an image with characters or words in it that the user is to re-type. The image is usually distorted and has some noise applied to it to make the characters difficult to read. Provide text alternatives that identify the image and describes further output modes. Provide alternative forms of the CAPTCHA using output modes for different types of sensory perception. For instance provide an audio alternative along with the visual image. Locate the audio option right next to the visual one. This helps but is still problematic for people without sound cards, the deaf-blind, and some low hearing people. Another method is to include a form that asks a question along with the visual image. This helps but is can be problematic for people with cognitive impairments. Examples: * An obscured image of textual characters * An obscured image of a word Example 1 Head: A CAPTCHA test which uses a distorted image of text. Example 1 Description: <img src="captcha.png" alt="CAPTCHA image: If you cannot read the text in this image, an audio challenge and questionnaire follow."> <!-- audio CAPTCHA option that allows the user to listen and type the word --> <!-- form that asks a question --> Resource 1 Title: Web Design References: Accessibility CAPTCHA Resource 1 URI: http://www.d.umn.edu/itss/support/Training/Online/webdesign/accessibility.html#captcha Related Techniques: G143 G144 H37 Test Procedure: 1. Check that the purpose of the non-text content is clear - even if function is lost and that the Web page contains another CAPTCHA for the same purpose but using a different modality. Expected Result: #1 is true. Additional Notes: his technique is part of the HTMLWG's Action 54: First Draft http://esw.w3.org/topic/HTML/Action54AltAttribute If it is accepted by WCAG we hope to remove it from our document as stated in the second draft http://esw.w3.org/topic/HTML/Action54AltAttributeSecondDraft#head-f0bf2ebf9f3e1fa190974101c6b70700ff176772 The Action 54 first draft provides much non-normative guidance in the application of the ALT attribute, which may not be appropriate for inclusion in a markup language specification, and which moreover could be seen as usurping the role of WCAG 2.0 and its techniques documents. A format specification is not a tutorial. It would be very helpful if the Techniques for WCAG 2.0. could incorporate this information or a variation of it. Then the HTML5 spec could link to it. As PF has said, "WCAG WG is chartered to set Accessibility guidelines and HTML WG is not". http://lists.w3.org/Archives/Public/public-html/2008Feb/0082.html Thank you, The HTMLWG Action 54 Team: Steven Faulkner Joshue O Connor Laura Carlson Peer reviewers: Gez Lemon Gregory Rosmaita No example 2 header was submitted! No example 2 description was submitted! No resource 2 title submitted! No resource 2 URI submitted! No test file 1 was submitted! No test file 1 pass/fail was submitted! No test file 2 was submitted! No test file 2 pass/fail was submitted! ------------------------------------------------ <technique id="UNKNOWN"> <short-name>Providing Text Alternatives for CAPTCHA Images.</short-name> <applies-to> <guideline idref="text-equiv" /> <success-criterion idref="UNKNOWN" /> </applies-to> <applicability> Applies to HTML </applicability> <ua_issues> None known </ua_issues> <description> The objective of this technique is explain and demonstrate how to markup CAPTCHA Images. CAPTCHA stands for "Completely Automated Public Turing test to tell Computers and Humans Apart". CAPTCHA images are used for security purposes to confirm that content is being accessed by a person rather than a computer. This authentication is done through visual verification of an image. CAPTCHA typically presents an image with characters or words in it that the user is to re-type. The image is usually distorted and has some noise applied to it to make the characters difficult to read. Provide text alternatives that identify the image and describes further output modes. Provide alternative forms of the CAPTCHA using output modes for different types of sensory perception. For instance provide an audio alternative along with the visual image. Locate the audio option right next to the visual one. This helps but is still problematic for people without sound cards, the deaf-blind, and some low hearing people. Another method is to include a form that asks a question along with the visual image. This helps but is can be problematic for people with cognitive impairments. Examples: * An obscured image of textual characters * An obscured image of a word </description> <examples> <ex_head_1> A CAPTCHA test which uses a distorted image of text. </ex_head_1> <ex_desc_1> <img src="captcha.png" alt="CAPTCHA image: If you cannot read the text in this image, an audio challenge and questionnaire follow."> <!-- audio CAPTCHA option that allows the user to listen and type the word --> <!-- form that asks a question --> </ex_desc_1> <ex_head_2> </ex_head_2> <ex_desc_2> </ex_desc_2> </examples> <resources> <resources_title1> Web Design References: Accessibility CAPTCHA </resources_title1> <resource_uri1> http://www.d.umn.edu/itss/support/Training/Online/webdesign/accessibility.html#captcha </resource_uri1> <resources_title2> </resources_title2> <resource_uri2> </resource_uri2> </resources> <related_techniques> <related_technique> G143 </related_technique> <related_technique> G144 </related_technique> <related_technique> H37 </related_technique> </related_techniques> <tests> <procedure> 1. Check that the purpose of the non-text content is clear - even if function is lost and that the Web page contains another CAPTCHA for the same purpose but using a different modality. </procedure> <expected_result> #1 is true. </expected_result> <test_file_1> </test_file_1> <pass_fail_1> </pass_fail_1> <test_file_2> </test_file_2> <pass_fail_2> </pass_fail_2> </tests> </technique> Additional Notes: his technique is part of the HTMLWG's Action 54: First Draft http://esw.w3.org/topic/HTML/Action54AltAttribute If it is accepted by WCAG we hope to remove it from our document as stated in the second draft http://esw.w3.org/topic/HTML/Action54AltAttributeSecondDraft#head-f0bf2ebf9f3e1fa190974101c6b70700ff176772 The Action 54 first draft provides much non-normative guidance in the application of the ALT attribute, which may not be appropriate for inclusion in a markup language specification, and which moreover could be seen as usurping the role of WCAG 2.0 and its techniques documents. A format specification is not a tutorial. It would be very helpful if the Techniques for WCAG 2.0. could incorporate this information or a variation of it. Then the HTML5 spec could link to it. As PF has said, "WCAG WG is chartered to set Accessibility guidelines and HTML WG is not". http://lists.w3.org/Archives/Public/public-html/2008Feb/0082.html Thank you, The HTMLWG Action 54 Team: Steven Faulkner Joshue O Connor Laura Carlson Peer reviewers: Gez Lemon Gregory Rosmaita
Received on Wednesday, 4 June 2008 16:57:43 UTC