diff --git a/layout/html/document/src/html.css b/layout/html/document/src/html.css
index 91639ab41785..1a133934cee0 100644
--- a/layout/html/document/src/html.css
+++ b/layout/html/document/src/html.css
@@ -437,6 +437,16 @@ marquee {
 
 marquee[direction="up"], marquee[direction="down"] {
   -moz-binding: url('chrome://xbl-marquee/content/xbl-marquee.xml#marquee-vertical');
+  height: 200px;
+}
+
+/* Marquees with a height attr that actually specifies a height should have
+   auto CSS height here.  Note that this rule has the same specificity as the
+   preceding one, so it has to come later in the sheet to work. */
+marquee[height*="1"], marquee[height*="2"], marquee[height*="3"],
+marquee[height*="4"], marquee[height*="5"], marquee[height*="6"],
+marquee[height*="7"], marquee[height*="8"], marquee[height*="9"] {
+  height: auto;
 }
 
 /* PRINT ONLY rules follow */
diff --git a/layout/style/html.css b/layout/style/html.css
index 91639ab41785..1a133934cee0 100644
--- a/layout/style/html.css
+++ b/layout/style/html.css
@@ -437,6 +437,16 @@ marquee {
 
 marquee[direction="up"], marquee[direction="down"] {
   -moz-binding: url('chrome://xbl-marquee/content/xbl-marquee.xml#marquee-vertical');
+  height: 200px;
+}
+
+/* Marquees with a height attr that actually specifies a height should have
+   auto CSS height here.  Note that this rule has the same specificity as the
+   preceding one, so it has to come later in the sheet to work. */
+marquee[height*="1"], marquee[height*="2"], marquee[height*="3"],
+marquee[height*="4"], marquee[height*="5"], marquee[height*="6"],
+marquee[height*="7"], marquee[height*="8"], marquee[height*="9"] {
+  height: auto;
 }
 
 /* PRINT ONLY rules follow */