Clean up language around form submission and URLs

Also fix a bigger issue where we have an Otherwise clause without a
leading If clause. Pass encoding always as parameter.

source

@@ -13915,9 +13915,9 @@ people expect to have work and what is necessary.
   in the <span data-x="attr-meta-http-equiv-content-type">Encoding declaration state</span>.</p>
 
   <p class="note">A character encoding declaration is required (either in the <span
-  data-x="Content-Type">Content-Type metadata</span> or explicitly in the file) even if the encoding
-  is US-ASCII, because a character encoding is needed to process non-ASCII characters entered by the
-  user in forms, in URLs generated by scripts, and so forth.</p>
+  data-x="Content-Type">Content-Type metadata</span> or explicitly in the file) even when all
+  characters are in the ASCII range, because a character encoding is needed to process non-ASCII
+  characters entered by the user in forms, in URLs generated by scripts, and so forth.</p>
 
   <p>If the document is <span>an <code>iframe</code> <code data-x="attr-iframe-srcdoc">srcdoc</code>
   document</span>, the document must not have a <span>character encoding declaration</span>. (In
@@ -54424,6 +54424,9 @@ fur
    <li><p>Let <var>form data set</var> be the result of <span>constructing the form data
    set</span> for <var>form</var> in the context of <var>submitter</var>.</p></li>
 
+   <li><p>Let <var>encoding</var> be the result of <span>picking an encoding for the
+   form</span>.</p>
+
    <li><p>Let <var>action</var> be the <var>submitter</var> element's <span
    data-x="concept-fs-action">action</span>.</p></li>
 
@@ -54572,25 +54575,22 @@ fur
      <dt><dfn data-x="submit-mutate-action">Mutate action URL</dfn>
      <dd>
 
-      <p>Let <var>query</var> be the result of encoding the <var>form data
-      set</var> using the <span><code data-x="">application/x-www-form-urlencoded</code> encoding
-      algorithm</span>, interpreted as a US-ASCII string.</p>
+      <p>Let <var>query</var> be the result of running the <span><code
+      data-x="">application/x-www-form-urlencoded</code> encoding algorithm</span> with <var>form
+      data set</var> and <var>encoding</var>, interpreted as a US-ASCII string.</p>
 
       <p>Set <var>parsed action</var>'s <span data-x="concept-url-query">query</span>
       component to <var>query</var>.</p>
 
-      <p>Let <var>destination</var> be a new <span>URL</span> formed by applying the
-      <span data-x="concept-url-serialiser">URL serialiser</span> algorithm to <var>parsed action</var>.</p>
-
-      <p><span>Plan to navigate</span> to <var>destination</var>.</p>
+      <p><span>Plan to navigate</span> to <var>parsed action</var>.</p>
 
      </dd>
 
      <dt><dfn data-x="submit-body">Submit as entity body</dfn>
      <dd>
 
-      <p>Let <var>entity body</var> be the result of encoding the <var>form data
-      set</var> using the <span>appropriate form encoding algorithm</span>.</p>
+      <p>Let <var>entity body</var> be the result of running the <span>appropriate form encoding
+      algorithm</span> with <var>form data set</var> and <var>encoding</var>.</p>
 
       <p>Let <var>MIME type</var> be determined as follows:</p>
 
@@ -54617,15 +54617,10 @@ fur
 
       </dl>
 
-      <!--<p>If <var>method</var> is anything but (GET or) POST, and the
-      <span>origin</span> of <var>action</var> is not the <span>same origin</span> as that
-      of <var>form document</var>, then abort these steps.</p> [or do CORS] (this is
-      commented out since only POST can trigger this now, and that's historically unrestricted)-->
-
-      <p>Otherwise, <span>plan to navigate</span> to a new <span
-      data-x="concept-request">request</span> whose <span data-x="concept-request-url">url</span> is
-      <var>action</var>, <span data-x="concept-request-method">method</span> is <var>method</var>,
-      <span data-x="concept-request-header-list">header list</span> consists of `<code
+      <p><span>Plan to navigate</span> to a new <span data-x="concept-request">request</span> whose
+      <span data-x="concept-request-url">url</span> is <var>parsed action</var>, <span
+      data-x="concept-request-method">method</span> is <var>method</var>, <span
+      data-x="concept-request-header-list">header list</span> consists of `<code
       data-x="">Content-Type</code>`/<var>MIME type</var>, and <span
       data-x="concept-request-body">body</span> is <var>entity body</var>.</p>
 
@@ -54634,55 +54629,48 @@ fur
      <dt><dfn data-x="submit-get-action">Get action URL</dfn>
      <dd>
 
-      <p><span>Plan to navigate</span> to <var>action</var>.</p>
+      <p><span>Plan to navigate</span> to <var>parsed action</var>.</p>
 
       <p class="note">The <var>form data set</var> is discarded.</p>
 
      </dd>
 
      <dt><dfn data-x="submit-mailto-headers">Mail with headers</dfn>
      <dd>
-
-      <p>Let <var>headers</var> be the resulting encoding the <var>form data
-      set</var> using the <span><code data-x="">application/x-www-form-urlencoded</code> encoding
-      algorithm</span>, interpreted as a US-ASCII string.</p>
+      <p>Let <var>headers</var> be the result of running the <span><code
+      data-x="">application/x-www-form-urlencoded</code> encoding algorithm</span> with <var>form
+      data set</var> and <var>encoding</var>, interpreted as a US-ASCII string.</p>
 
       <p>Replace occurrences of U+002B PLUS SIGN characters (+) in <var>headers</var> with
       the string "<code data-x="">%20</code>".</p>
 
-      <p>Let <var>destination</var> consist of all the characters from the first character
-      in <var>action</var> to the character immediately before the first U+003F QUESTION
-      MARK character (?), if any, or the end of the string if there are none.</p>
-
-      <p>Append a single U+003F QUESTION MARK character (?) to <var>destination</var>.</p>
-
-      <p>Append <var>headers</var> to <var>destination</var>.</p>
-
-      <p><span>Plan to navigate</span> to <var>destination</var>.</p>
+      <p>Set <var>parsed action</var>'s <span data-x="concept-url-query">query</span> to
+      <var>headers</var>.</p>
 
+      <p><span>Plan to navigate</span> to <var>parsed action</var>.</p>
      </dd>
 
      <dt><dfn data-x="submit-mailto-body">Mail as body</dfn>
      <dd>
-
-      <p>Let <var>body</var> be the resulting of encoding the <var>form data
-      set</var> using the <span>appropriate form encoding algorithm</span> and then <span
+      <p>Let <var>body</var> be the resulting of running the <span>appropriate form encoding
+      algorithm</span> with <var>form data set</var> and <var>encoding</var>, and then <span
       data-x="percent encode">percent encoding</span> all the bytes in the resulting byte string
       that, when interpreted as US-ASCII, are not characters in the URL <span>default encode
       set</span>. <ref spec=URL></p>
 
-      <p>Let <var>destination</var> have the same value as <var>action</var>.</p>
-
-      <p>If <var>destination</var> does not contain a U+003F QUESTION MARK character (?),
-      append a single U+003F QUESTION MARK character (?) to <var>destination</var>.
-      Otherwise, append a single U+0026 AMPERSAND character (&amp;).</p>
+      <p>If <var>parsed action</var>'s <span data-x="concept-url-query">query</span> is null, then
+      set it to the empty string.
 
-      <p>Append the string "<code data-x="">body=</code>" to <var>destination</var>.</p>
+      <p>If <var>parsed action</var>'s <span data-x="concept-url-query">query</span> is not the
+      empty string, then append a single U+0026 AMPERSAND character (&amp;) to it.
 
-      <p>Append <var>body</var>, interpreted as a US-ASCII string, to <var>destination</var>.</p>
+      <p>Append "<code data-x="">body=</code>" to <var>parsed action</var>'s <span
+      data-x="concept-url-query">query</span>.</p>
 
-      <p><span>Plan to navigate</span> to <var>destination</var>.</p>
+      <p>Append <var>body</var>, interpreted as a US-ASCII string, to <var>parsed action</var>'s
+      <span data-x="concept-url-query">query</span>.</p>
 
+      <p><span>Plan to navigate</span> to <var>parsed action</var>.</p>
      </dd>
 
 
@@ -55008,14 +54996,12 @@ fur
 
   <div w-nodev>
 
-  <p id="application-x-www-form-urlencoded-encoding-algorithm">The <dfn><code data-x="">application/x-www-form-urlencoded</code> encoding algorithm</dfn> is as
-  follows:</p>
+  <p id="application-x-www-form-urlencoded-encoding-algorithm">The <dfn><code
+  data-x="">application/x-www-form-urlencoded</code> encoding algorithm</dfn>, given a <var>form
+  data set</var> and <var>encoding</var>, is as follows:</p>
 
   <ol>
 
-   <li><p>Let <var>encoding</var> be the result of <span>picking an encoding for the
-   form</span>.</p>
-
    <li><p>Let <var>serialized</var> be the result of running the
    <span><code>application/x-www-form-urlencoded</code> serializer</span> given <var>form data
    set</var> and <var>encoding</var>.</p></li>
@@ -55035,28 +55021,17 @@ fur
 
   <!-- NOTE: This algorithm is also used by the XHR spec -->
 
-  <p>The <dfn><code>multipart/form-data</code> encoding algorithm</dfn> is as follows:</p>
+  <p>The <dfn><code>multipart/form-data</code> encoding algorithm</dfn>, given a <var>form data
+  set</var> and <var>encoding</var>, is as follows:</p>
 
   <ol>
 
    <!-- the first few steps of this are the same as in the previous section -->
 
    <li><p>Let <var>result</var> be the empty string.</p></li>
 
-   <li>
-
-    <p>If the algorithm was invoked with an explicit character encoding, let the selected character
-    encoding be that encoding. (This algorithm is used by other specifications, which provide an
-    explicit character encoding to avoid the dependency on the <code>form</code> element described
-    in the next paragraph.)</p>
-
-    <p>Otherwise, let the selected character encoding be the result of <span>picking an encoding for
-    the form</span>.</p>
-
-   </li>
-
-   <li><p>Let <var>charset</var> be the <span data-x="encoding name">name</span> of the
-   selected <span data-x="encoding">character encoding</span>.</p></li>
+   <li><p>Let <var>charset</var> be the <span data-x="encoding name">name</span> of
+   <var>encoding</var>.</p></li>
 
    <li>
 
@@ -55119,20 +55094,17 @@ fur
   spec=RFC7578></p>
 
 
-
   <h5>Plain text form data</h5>
 
   <div w-nodev>
 
-  <p>The <dfn><code data-x="">text/plain</code> encoding algorithm</dfn> is as follows:</p>
+  <p>The <dfn><code data-x="">text/plain</code> encoding algorithm</dfn>, given a <var>form data
+  set</var> and <var>encoding</var>, is as follows:</p>
 
   <ol>
 
    <li><p>Let <var>result</var> be the empty string.</p></li>
 
-   <li><p>Let <var>encoding</var> be the result of <span>picking an encoding for the
-   form</span>.</p>
-
    <li><p>Let <var>charset</var> be the <span data-x="encoding name">name</span> of
    <var>encoding</var>.</p></li>