Correct <input type=image> form submission behavior

Tests: xhr/formdata/constructor-submitter.html.

Closes #8785.

Author: annevk

source

@@ -49655,29 +49655,25 @@ ldh-str       = &lt; as defined in <a href="https://www.rfc-editor.org/rfc/rfc10
    <li><p>If the element's <span>node document</span> is not <span>fully active</span>, then
    return.</p></li>
 
-   <li><p>Let <var>coordinate</var> be (0, 0).</p></li>
-
    <li>
-    <p>If the user activated the control while explicitly selecting a coordinate, then set
-    <var>coordinate</var> to that coordinate.</p>
+    <p>If the user activated the control while explicitly selecting a coordinate, then set the
+    element's <span data-x="concept-input-type-image-coordinate">selected coordinate</span> to that
+    coordinate.</p>
 
     <p class="note">This is only possible under the conditions outlined above, when the element
     <span>represents</span> a control for selecting such a coordinate. Even then, the user
     might activate the control without explicitly selecting a coordinate.</p>
    </li>
 
-   <li><p>Set the element's <span data-x="concept-input-type-image-coordinate">selected
-   coordinate</span> to <var>coordinate</var>.</p></li>
-
    <li><p><span data-x="concept-form-submit">Submit</span> the <span>form owner</span> from the
    element.</p></li>
   </ol>
 
-  <p>The <dfn data-x="concept-input-type-image-coordinate">selected coordinate</dfn> must consist of
-  an <var>x</var>-component and a <var>y</var>-component. The coordinates
-  represent the position relative to the edge of the image, with the coordinate space having the
-  positive <var>x</var> direction to the right, and the positive <var>y</var>
-  direction downwards.</p>
+  <p>The element's <dfn data-x="concept-input-type-image-coordinate">selected coordinate</dfn>
+  consists of an <var>x</var>-component and a <var>y</var>-component. It is initially (0, 0). The
+  coordinates represent the position relative to the edge of the element's image, with the
+  coordinate space having the positive <var>x</var> direction to the right, and the positive
+  <var>y</var> direction downwards.</p>
 
   <p>The <var>x</var>-component must be a <span>valid integer</span> representing a number
   <var>x</var> in the range <span data-x="">&#x2212;(<var>border<sub>left</sub></var>+<var>padding<sub>left</sub></var>) &le; <var>x</var> &le; <var>width</var>+<var>border<sub>right</sub></var>+<var>padding<sub>right</sub></var></span>, where <var>width</var> is the rendered width of the image, <var>border<sub>left</sub></var> is the width of the border on the left of the image, <var>padding<sub>left</sub></var> is the width of the padding on the left of the
@@ -58390,23 +58386,21 @@ fur
       data-x="attr-input-type-image">Image Button</span> state, then:</p>
 
       <ol>
+       <li><p>If the <var>field</var> element is not <var>submitter</var>, then
+       <span>continue</span>.</p></li>
+
        <li><p>If the <var>field</var> element has a <code data-x="attr-fe-name">name</code>
-       attribute specified and its value is not the empty string, let <var>name</var> be
-       that value followed by a single U+002E FULL STOP character (.). Otherwise, let <var>name</var> be the empty string.</p></li>
-
-       <li><p>Let <var>name<sub>x</sub></var> be the string consisting of the
-       concatenation of <var>name</var> and a single U+0078 LATIN SMALL LETTER X character
-       (x).</p></li>
-
-       <li><p>Let <var>name<sub>y</sub></var> be the string consisting of the
-       concatenation of <var>name</var> and a single U+0079 LATIN SMALL LETTER Y character
-       (y).</p></li>
-
-       <li><p>The <var>field</var> element is <var>submitter</var>, and before
-       this algorithm was invoked the user <span
-       data-x="concept-input-type-image-coordinate">indicated a coordinate</span>. Let <var>x</var> be the <var>x</var>-component of the coordinate selected by the
-       user, and let <var>y</var> be the <var>y</var>-component of the coordinate
-       selected by the user.</p></li>
+       attribute specified and its value is not the empty string, let <var>name</var> be that value
+       followed by U+002E (.). Otherwise, let <var>name</var> be the empty string.</p></li>
+
+       <li><p>Let <var>name<sub>x</sub></var> be the concatenation of <var>name</var> and
+       U+0078 (x).</p></li>
+
+       <li><p>Let <var>name<sub>y</sub></var> be the concatenation of <var>name</var> and
+       U+0079 (y).</p></li>
+
+       <li><p>Let (<var>x</var>, <var>y</var>) be the <span
+       data-x="concept-input-type-image-coordinate">selected coordinate</span>.</p></li>
 
        <li><p><span>Create an entry</span> with <var>name<sub>x</sub></var> and <var>x</var>, and
        <span data-x="list append">append</span> it to <var>entry list</var>.</p></li>