rewrite of intro as per issue #66

Clarify relationship between html-aam and core-aam mappings

Author: jasonkiss

index.html

@@ -118,15 +118,15 @@
   section>
   <section id="intro" class="informative">
     <h2>Introductionh2>
-    <p>Like the <a href="http://www.w3.org/TR/core-aam-1.1/">Core Accessibility API Mappingsa> specification, this document defines how HTML user agents must respond to keyboard focus, as well as <a class="termref">rolea>, <a class="termref">statea> and <a class="termref">propertya> information provided for Web content. Where an HTML element or attribute has default <cite><a href="http://www.w3.org/TR/wai-aria-1.1/">Accessible Rich Internet Applications (<abbr title="Accessible Rich Internet Applications">WAI-ARIAabbr>) 1.1a>cite> [[!WAI-ARIA]] semantics, it must be exposed to the platform <a class="termref" data-lt="Accessibility API">accessibility APIsa> according to the relevant WAI-ARIA mappings defined in the <a href="http://www.w3.org/TR/core-aam-1.1/">Core Accessibility API Mappingsa> specification. Where an HTML element or attribute does not have default WAI-ARIA semantics, the applicable mapping for each platform <a class="termref" data-lt="Accessibility API">accessibility APIa> is defined by this specification.p>
+    <p>This specification defines how HTML user agents must respond to and expose <a class="termref">rolea>, <a class="termref">statea> and <a class="termref">propertya> information provided for Web content. Unless indicated otherwise, an HTML element or attribute with default <cite><a href="http://www.w3.org/TR/wai-aria-1.1/">Accessible Rich Internet Applications (<abbr title="Accessible Rich Internet Applications">WAI-ARIAabbr>) 1.1a>cite> [[!WAI-ARIA]] semantics must be exposed to the platform <a class="termref" data-lt="Accessibility API">accessibility APIsa> according to the relevant WAI-ARIA mappings defined in the <a href="http://www.w3.org/TR/core-aam-1.1/">Core Accessibility API Mappingsa> [[!CORE-AAM]] specification. In some cases, often due to features of the HTML host language or the accessibility API in question, an element or attribute's mapping differs from the corresponding ARIA mappings specified in the [[!CORE-AAM]]. Where an HTML element or attribute does not have any default WAI-ARIA semantics, the applicable mapping for each platform <a class="termref" data-lt="Accessibility API">accessibility APIa> is defined by this specification.p>
     <p>This document also adapts the <a href="http://www.w3.org/TR/accname-aam-1.1/">Accessible Name and Description: Computation and API Mappingsa> [[!ACCNAME-AAM]] for deriving the <a class="termref" data-lt="Accessible Name">accessible namesa> and <a class="termref" data-lt="Accessible Description">accessible descriptionsa> of HTML 5.1 [[!HTML51]] elements, and provides accessible implementation examples for specific HTML 5.1 elements and features.p>
     <p>Users often access HTML content using assistive technologies that rely on platform <a class="termref">accessibility <abbr title="Application Programming Interface">APIabbr>a> to obtain and interact with information from the page. This document is part of the following suite of accessibility API mapping specifications for content rendered by user agents: p>
     <ul>
        <li><cite><a href="http://www.w3.org/TR/accname-aam-1.1/">Accessible Name and Description: Computation and API Mappingsa>cite> [[!ACCNAME-AAM]]li>
        <li><cite><a href="http://www.w3.org/TR/core-aam-1.1/">Core Accessibility API Mappingsa>cite> [[!CORE-AAM]]li>
        <li><cite><a href="http://www.w3.org/TR/html-aam-1.0/">HTML Accessibility API Mappingsa>cite> [[HTML-AAM]]li>
        <li><cite><a href="http://www.w3.org/TR/svg-aam-1.0/">SVG Accessibility API Mappingsa>cite> [[SVG-AAM]]li>
-    ul>      
+    ul> 
     <section id="intro_aapi">
       <h3>Accessibility APIsh3>
       <p><a class="termref" data-lt="Accessibility API">Accessibility APIsa> covered by this document are:p>
@@ -5914,6 +5914,7 @@ Change Log
         <section>
           <h4>Substantive changes since moving entirely to the Web Platform Working Group (01-Oct-2016)h4>
           <ul>
+            <li>18-Dec-2017: Rewrote first paragraph in Introduction> to better reflect the relationship between the HTML-AAM and CORE-AAM specifications. See <a href="https://github.com/w3c/html-aam/issues/66">GitHub issue #66a>.li>
             <li>18-Dec-2017: Updated <code>readonlycode> attribute to use <code>aria-readonly="true"code> WAI-ARIA mappings. See <a href="https://github.com/w3c/html-aam/issues/93">GitHub issue #93a>.li>
             <li>08-Dec-2017: Changed AXAPI mapping for the <code>canvascode> element from <code>AXImagecode> to <code>AXGroupcode>.li>
             <li>01-Dec-2017: Updated mappings for the <code>dfncode> element. See <a href="https://github.com/w3c/html-aam/issues/6">GitHub issue #6a>.li>