Don't update document.currentScript for module scripts

domenic · annevk · commit 69182823e3da · 2016-04-15T08:54:41.000+02:00
Make module scripts modify less global script state. They set document.currentScript to null, and no longer fire beforescriptexecute and afterscriptexecute events. Closes #997. See #1013 for a future alternative to document.currentScript, and #943 for more discussion of the events.
diff --git a/source b/source
@@ -3113,7 +3113,7 @@ a.setAttribute('href', 'http://example.com/'); // change the content attribute d
      <li><dfn data-noexport="" data-x="dom-Element-id" data-x-href="https://dom.spec.whatwg.org/#dom-element-id"><code>id</code></dfn> attribute</li>
      <li><dfn data-noexport="" data-x-href="https://dom.spec.whatwg.org/#dom-node-textcontent"><code>textContent</code></dfn> attribute</li>
 
-     <li>The <dfn data-noexport="" data-x-href="https://dom.spec.whatwg.org/#concept-tree">tree</dfn> concept</li>
+     <li>The <dfn data-noexport="" data-x-href="https://dom.spec.whatwg.org/#concept-tree">tree</dfn> and <dfn data-noexport="" data-x-href="https://dom.spec.whatwg.org/#concept-shadow-tree">shadow tree</dfn> concepts</li>
      <li>The <dfn data-noexport="" data-x-href="https://dom.spec.whatwg.org/#concept-tree-order">tree order</dfn> concept</li>
      <li>The <dfn data-noexport="" data-x-href="https://dom.spec.whatwg.org/#concept-tree-root">root</dfn> concept</li>
      <li>The <dfn data-noexport="" data-x-href="https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor">inclusive ancestor</dfn> concept</li>
@@ -8536,7 +8536,7 @@ partial /*sealed*/ interface <dfn>Document</dfn> {
   [SameObject] readonly attribute <span>HTMLCollection</span> <span data-x="dom-document-forms">forms</span>;
   [SameObject] readonly attribute <span>HTMLCollection</span> <span data-x="dom-document-scripts">scripts</span>;
   NodeList <span data-x="dom-document-getElementsByName">getElementsByName</span>(DOMString elementName);
-  readonly attribute <span>HTMLOrSVGScriptElement</span>? <span data-x="dom-document-currentScript">currentScript</span>;
+  readonly attribute <span>HTMLOrSVGScriptElement</span>? <span data-x="dom-document-currentScript">currentScript</span>; // classic scripts in a document only
 
   // <span>dynamic markup insertion</span>
   <span>Document</span> <span data-x="dom-document-open">open</span>(optional DOMString type = "text/html", optional DOMString replace = "");
@@ -9053,12 +9053,14 @@ partial /*sealed*/ interface <dfn>Document</dfn> {
    <dd>
 
     <p>Returns the <code>script</code> element, or the <span>SVG <code>script</code></span> element,
-    that is currently executing. In the case of reentrant script execution, returns the one that
-    most recently started executing amongst those that have not yet finished executing.</p>
+    that is currently executing, as long as the element represents a <span>classic script</span>.
+    In the case of reentrant script execution, returns the one that most recently started executing
+    amongst those that have not yet finished executing.</p>
 
     <p>Returns null if the <code>Document</code> is not currently executing a <code>script</code>
     or <span>SVG <code>script</code></span> element (e.g., because the running script is an event
-    handler, or a timeout).</p>
+    handler, or a timeout), or if the currently executing <code>script</code> or <span>SVG
+    <code>script</code></span> element represents a <span>module script</span>.</p>
 
    </dd>
 
@@ -9067,12 +9069,19 @@ partial /*sealed*/ interface <dfn>Document</dfn> {
   <div w-nodev>
 
   <p>The <dfn><code data-x="dom-document-currentScript">currentScript</code></dfn> attribute, on
-  getting, must return the value to which it was most recently initialised. When the
-  <code>Document</code> is created, the <code
-  data-x="dom-document-currentScript">currentScript</code> must be initialised to null.</p>
+  getting, must return the value to which it was most recently set. When the <code>Document</code>
+  is created, the <code data-x="dom-document-currentScript">currentScript</code> must be
+  initialised to null.</p>
 
   </div>
 
+  <p class="note">This API has fallen out of favor in the implementor and standards community, as
+  it globally exposes <code>script</code> or <span>SVG <code>script</code></span> elements. As such,
+  it is not available in newer contexts, such as when running <span data-x="module script">module
+  scripts</span> or when running scripts in a <span>shadow tree</span>. We are looking into creating
+  a new solution for identifying the running script in such contexts, which does not make it
+  globally available: see issue <a href="https://github.com/whatwg/html/issues/1013">#1013</a>.</p>
+
   <div w-nodev>
 
   <hr>
@@ -59012,7 +59021,8 @@ o............A....e
 
    <li>
 
-    <p><span>Fire a simple event</span> named <code
+    <p>If <span data-x="concept-script-type">the script's type</span> is "<code
+    data-x="">classic</code>", <span>fire a simple event</span> named <code
     data-x="event-beforescriptexecute">beforescriptexecute</code> that bubbles and is cancelable
     at the <code>script</code> element.</p>
 
@@ -59035,22 +59045,7 @@ o............A....e
     <p>Let <var>old script element</var> be the value to which the <code>script</code>
     element's <span>node document</span>'s <code
     data-x="dom-document-currentScript">currentScript</code> object was most recently
-    initialised.</p>
-
-   </li>
-
-   <li>
-
-    <p>Initialise the <code>script</code> element's <span>node document</span>'s <code
-    data-x="dom-document-currentScript">currentScript</code> object to the <code>script</code>
-    element.</p>
-
-   </li>
-
-   <li>
-
-    <p>Let <var>settings object</var> be the <span>environment settings object</span> of the
-    <code>script</code> element's <span>node document</span>'s <code>Window</code> object.</p>
+    set.</p>
 
    </li>
 
@@ -59061,23 +59056,34 @@ o............A....e
     <dl class="switch">
      <dt>"<code data-x="">classic</code>"</dt>
      <dd>
-      <p><span data-x="run a classic script">Run the classic script</span> given by <span
-      data-x="concept-script-script">the script's script</span>.</p>
+      <ol>
+       <li><p>Set the <code>script</code> element's <span>node document</span>'s <code
+       data-x="dom-document-currentScript">currentScript</code> attribute to the
+       <code>script</code> element.</p></li>
+
+       <li><p><span data-x="run a classic script">Run the classic script</span> given by <span
+       data-x="concept-script-script">the script's script</span>.</p></li>
+      </ol>
      </dd>
 
      <dt>"<code data-x="">module</code>"</dt>
      <dd>
-      <p><span data-x="run a module script">Run the module script</span> given by <span
-      data-x="concept-script-script">the script's script</span>.</p>
+      <ol>
+       <li><p>Set the <code>script</code> element's <span>node document</span>'s <code
+       data-x="dom-document-currentScript">currentScript</code> attribute to null.</p></li>
+
+       <li><p><span data-x="run a module script">Run the module script</span> given by <span
+       data-x="concept-script-script">the script's script</span>.</p></li>
+      </ol>
      </dd>
     </dl>
 
    </li>
 
    <li>
 
-    <p>Initialise the <code>script</code> element's <span>node document</span>'s <code
-    data-x="dom-document-currentScript">currentScript</code> object to <var>old script
+    <p>Set the <code>script</code> element's <span>node document</span>'s <code
+    data-x="dom-document-currentScript">currentScript</code> attribute to <var>old script
     element</var>.</p>
 
    </li>
@@ -59090,7 +59096,8 @@ o............A....e
 
    <li>
 
-    <p><span>Fire a simple event</span> named <code
+    <p>If <span data-x="concept-script-type">the script's type</span> is "<code
+    data-x="">classic</code>", <span>fire a simple event</span> named <code
     data-x="event-afterscriptexecute">afterscriptexecute</code> that bubbles (but is not
     cancelable) at the <code>script</code> element.</p>
 
