diff --git a/cssom-view-1/Overview.bs b/cssom-view-1/Overview.bs
index 9376d0d3cb2..37529cdf26b 100644
--- a/cssom-view-1/Overview.bs
+++ b/cssom-view-1/Overview.bs
@@ -56,6 +56,10 @@ spec:css-borders-4; type:property; text:border-top-width
 spec:css-borders-4; type:property; text:border-left-width
 spec:cssom-view-1; type:dictionary; text:MouseEventInit
 spec:cssom-view-1; type:dfn; for:MediaQueryList; text:media
+spec:dom; type:interface; text:FormControlRange
+spec:dom; type:method; for:FormControlRange; text:getClientRects()
+spec:dom; type:method; for:FormControlRange; text:getBoundingClientRect()
+spec:dom; type:dfn; for:FormControlRange; text:value string
 </pre>
 
 <style>
@@ -2044,6 +2048,73 @@ Note: The {{DOMRect}} object returned by {{Range/getBoundingClientRect()}} is no
     range-bounding-client-rect-with-display-contents.html
 </wpt>
 
+<h2 id=extensions-to-the-formcontrolrange-interface> Extensions to the {{FormControlRange}}
+Interface</h2>
+
+This section defines {{FormControlRange/getClientRects()}} and
+{{FormControlRange/getBoundingClientRect()}} for {{FormControlRange}}. They mirror {{Range}}’s
+{{Range/getClientRects()}} and {{Range/getBoundingClientRect()}}, but operate on the selected
+portion of a text control’s {{FormControlRange/value string}}.
+
+The <dfn export for=FormControlRange>associated control</dfn> of a {{FormControlRange}} is the
+<code>&lt;textarea></code> or text-supporting <code>&lt;input></code> whose {{FormControlRange/value
+string}} the range indexes into.
+
+<p class=note>For consistency with {{Range}}, {{FormControlRange/getClientRects()}} returns an empty
+{{DOMRectList}} when the range is {{AbstractRange/collapsed}}.</p>
+
+<div algorithm="getClientRects() for FormControlRange">
+
+  The steps for {{FormControlRange/getClientRects()}} are the same as {{Range}}’s 
+  {{Range/getClientRects()}}, except that the rectangles are computed relative to the rendered text
+  within the control’s {{FormControlRange/value string}}.
+
+  <ol>
+    <li>If the <a>associated control</a> is not [=connected=] or its computed <code>display</code>
+    is <code>none</code>, return an empty {{DOMRectList}}.</li>
+
+    <li>Update style and layout for the <a>associated control</a>.</li>
+
+    <li>Let <var>value length</var> be the current length of the <a>associated control</a>’s
+    {{FormControlRange/value string}}.</li>
+
+    <li>Let <var>start</var> be min(<a>this</a>'s {{AbstractRange/startOffset}}, <var>value length</var>)
+    and let <var>end</var> be min(<a>this</a>'s {{AbstractRange/endOffset}}, <var>value length</var>).</li>
+
+    <li>If <var>start</var> = <var>end</var>, return an empty {{DOMRectList}}.</li>
+
+    <li>Let <var>text</var> be the single {{Text}} node that backs the control’s editable value. If
+    none, return an empty {{DOMRectList}}.</li>
+
+    <li>Let <var>r</var> be a {{Range}} whose start is (<var>text</var>, <var>start</var>) and whose
+    end is (<var>text</var>, <var>end</var>).</li>
+
+    <li>Return <var>r</var>.{{Range/getClientRects()}}.</li>
+  </ol>
+</div>
+
+<div algorithm="getBoundingClientRect() for FormControlRange">
+
+  The steps for {{FormControlRange/getBoundingClientRect()}} are the same as {{Range}}’s
+  {{Range/getBoundingClientRect()}}, except that the bounding rectangle is computed relative to the
+  rendered text within the control’s {{FormControlRange/value string}} .
+
+  <ol>
+    <li>Let <var>rects</var> be the result of {{FormControlRange/getClientRects()}}.</li>
+
+    <li>If <var>rects</var> is empty, return a {{DOMRect}} whose {{DOMRect/x}}, {{DOMRect/y}},
+    {{DOMRect/width}}, and {{DOMRect/height}} members are zero.</li>
+
+    <li>Otherwise, return a {{DOMRect}} describing the smallest rectangle that includes every
+    rectangle in <var>rects</var>, as for {{Range}}’s {{Range/getBoundingClientRect()}}.</li>
+  </ol>
+</div>
+
+<!-- WPT test names will be updated once they have been merged in. -->
+<wpt>
+  FormControlRange-geometry.html
+</wpt>
+
 <h2 id=extensions-to-the-mouseevent-interface>Extensions to the {{MouseEvent}} Interface</h2>
 
 Issue: The object IDL fragment redefines some members. Can we resolve this somehow?