--- a/layout/style/nsCSSParser.cpp
+++ b/layout/style/nsCSSParser.cpp
@@ -1304,16 +1304,17 @@ CSSParserImpl::GetToken(PRBool aSkipWS)
 }
 
 PRBool
 CSSParserImpl::GetURLInParens(nsString& aURL)
 {
   NS_ASSERTION(!mHavePushBack, "mustn't have pushback at this point");
   do {
     if (! mScanner.NextURL(mToken)) {
+      // EOF
       return PR_FALSE;
     }
   } while (eCSSToken_WhiteSpace == mToken.mType);
 
   aURL = mToken.mIdent;
 
   if ((eCSSToken_String != mToken.mType && eCSSToken_URL != mToken.mType) ||
       !ExpectSymbol(')', PR_TRUE)) {
@@ -3610,53 +3611,57 @@ CSSParserImpl::ParseColor(nsCSSValue& aV
         PRUint8 r, g, b;
         PRInt32 type = COLOR_TYPE_UNKNOWN;
         if (ParseColorComponent(r, type, ',') &&
             ParseColorComponent(g, type, ',') &&
             ParseColorComponent(b, type, ')')) {
           aValue.SetColorValue(NS_RGB(r,g,b));
           return PR_TRUE;
         }
-        return PR_FALSE;  // already pushed back
+        SkipUntil(')');
+        return PR_FALSE;
       }
       else if (mToken.mIdent.LowerCaseEqualsLiteral("-moz-rgba") ||
                mToken.mIdent.LowerCaseEqualsLiteral("rgba")) {
         // rgba ( component , component , component , opacity )
         PRUint8 r, g, b, a;
         PRInt32 type = COLOR_TYPE_UNKNOWN;
         if (ParseColorComponent(r, type, ',') &&
             ParseColorComponent(g, type, ',') &&
             ParseColorComponent(b, type, ',') &&
             ParseColorOpacity(a)) {
           aValue.SetColorValue(NS_RGBA(r, g, b, a));
           return PR_TRUE;
         }
-        return PR_FALSE;  // already pushed back
+        SkipUntil(')');
+        return PR_FALSE;
       }
       else if (mToken.mIdent.LowerCaseEqualsLiteral("hsl")) {
         // hsl ( hue , saturation , lightness )
         // "hue" is a number, "saturation" and "lightness" are percentages.
         if (ParseHSLColor(rgba, ')')) {
           aValue.SetColorValue(rgba);
           return PR_TRUE;
         }
+        SkipUntil(')');
         return PR_FALSE;
       }
       else if (mToken.mIdent.LowerCaseEqualsLiteral("-moz-hsla") ||
                mToken.mIdent.LowerCaseEqualsLiteral("hsla")) {
         // hsla ( hue , saturation , lightness , opacity )
         // "hue" is a number, "saturation" and "lightness" are percentages,
         // "opacity" is a number.
         PRUint8 a;
         if (ParseHSLColor(rgba, ',') &&
             ParseColorOpacity(a)) {
           aValue.SetColorValue(NS_RGBA(NS_GET_R(rgba), NS_GET_G(rgba),
                                        NS_GET_B(rgba), a));
           return PR_TRUE;
         }
+        SkipUntil(')');
         return PR_FALSE;
       }
       break;
     default:
       break;
   }
 
   // try 'xxyyzz' without '#' prefix for compatibility with IE and Nav4x (bug 23236 and 45804)
@@ -4469,22 +4474,30 @@ CSSParserImpl::ParseVariant(nsCSSValue& 
       (eCSSToken_Function == tk->mType) &&
       (tk->mIdent.LowerCaseEqualsLiteral("counter") ||
        tk->mIdent.LowerCaseEqualsLiteral("counters"))) {
     return ParseCounter(aValue);
   }
   if (((aVariantMask & VARIANT_ATTR) != 0) &&
       (eCSSToken_Function == tk->mType) &&
       tk->mIdent.LowerCaseEqualsLiteral("attr")) {
-    return ParseAttr(aValue);
+    if (!ParseAttr(aValue)) {
+      SkipUntil(')');
+      return PR_FALSE;
+    }
+    return PR_TRUE;
   }
   if (((aVariantMask & VARIANT_CUBIC_BEZIER) != 0) &&
       (eCSSToken_Function == tk->mType)) {
      if (tk->mIdent.LowerCaseEqualsLiteral("cubic-bezier")) {
-      return ParseTransitionTimingFunctionValues(aValue);
+      if (!ParseTransitionTimingFunctionValues(aValue)) {
+        SkipUntil(')');
+        return PR_FALSE;
+      }
+      return PR_TRUE;
     }
   }
   if ((aVariantMask & VARIANT_CALC) &&
       (eCSSToken_Function == tk->mType) &&
       (tk->mIdent.LowerCaseEqualsLiteral("-moz-calc") ||
        tk->mIdent.LowerCaseEqualsLiteral("-moz-min") ||
        tk->mIdent.LowerCaseEqualsLiteral("-moz-max"))) {
     // calc() currently allows only lengths and percents inside it.

--- a/layout/style/test/Makefile.in
+++ b/layout/style/test/Makefile.in
@@ -170,16 +170,17 @@ GARBAGE += css_properties.js
 		test_system_font_serialization.html \
 		test_transitions_computed_values.html \
 		test_transitions_computed_value_combinations.html \
 		test_transitions_events.html \
 		test_transitions.html \
 		test_transitions_per_property.html \
 		test_transitions_dynamic_changes.html \
 		test_transitions_bug537151.html \
+		test_unclosed_parentheses.html \
 		test_units_angle.html \
 		test_units_frequency.html \
 		test_units_length.html \
 		test_units_time.html \
 		test_value_cloning.html \
 		test_value_computation.html \
 		test_value_storage.html \
 		test_visited_image_loading.html \

--- a/layout/style/test/property_database.js
+++ b/layout/style/test/property_database.js
@@ -1026,17 +1026,20 @@ var gCSSProperties = {
 		"-moz-repeating-radial-gradient(99deg, cover, red, blue)",
 		"-moz-repeating-radial-gradient(-1.2345rad, circle, red, blue)",
 		"-moz-repeating-radial-gradient(399grad, ellipse closest-corner, red, blue)",
 		"-moz-repeating-radial-gradient(399grad, farthest-side circle, red, blue)",
 
 		"-moz-repeating-radial-gradient(top left 99deg, cover, red, blue)",
 		"-moz-repeating-radial-gradient(15% 20% -1.2345rad, circle, red, blue)",
 		"-moz-repeating-radial-gradient(45px 399grad, ellipse closest-corner, red, blue)",
-		"-moz-repeating-radial-gradient(45px 399grad, farthest-side circle, red, blue)"
+		"-moz-repeating-radial-gradient(45px 399grad, farthest-side circle, red, blue)",
+		"-moz-image-rect(url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAIAAAD8GO2jAAAAKElEQVR42u3NQQ0AAAgEoNP+nTWFDzcoQE1udQQCgUAgEAgEAsGTYAGjxAE/G/Q2tQAAAABJRU5ErkJggg==), 2, 10, 10, 2)",
+		"-moz-image-rect(url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAIAAAD8GO2jAAAAKElEQVR42u3NQQ0AAAgEoNP+nTWFDzcoQE1udQQCgUAgEAgEAsGTYAGjxAE/G/Q2tQAAAABJRU5ErkJggg==), 10%, 50%, 30%, 0%)",
+		"-moz-image-rect(url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAIAAAD8GO2jAAAAKElEQVR42u3NQQ0AAAgEoNP+nTWFDzcoQE1udQQCgUAgEAgEAsGTYAGjxAE/G/Q2tQAAAABJRU5ErkJggg==), 10, 50%, 30%, 0)",
 		],
 		invalid_values: [
 			/* Old syntax */
 			"-moz-linear-gradient(10px 10px, 20px, 30px 30px, 40px, from(blue), to(red))",
 			"-moz-radial-gradient(20px 20px, 10px 10px, from(green), to(#ff00ff))",
 			"-moz-radial-gradient(10px 10px, 20%, 40px 40px, 10px, from(green), to(#ff00ff))",
 			"-moz-linear-gradient(10px, 20px, 30px, 40px, color-stop(0.5, #00ccff))",
 			"-moz-linear-gradient(20px 20px, from(blue), to(red))",

new file mode 100644
--- /dev/null
+++ b/layout/style/test/test_unclosed_parentheses.html
@@ -0,0 +1,158 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=575672
+-->
+<head>
+  <title>Test for Bug 575672</title>
+  <script type="application/javascript" src="/MochiKit/packed.js"></script>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <style type="text/css" id="style"></style>
+  <style type="text/css">
+    #display { position: relative }
+  </style>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=575672">Mozilla Bug 575672</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for unclosed parentheses in CSS values. **/
+
+// Each of the following declarations should have a single missing ')'
+// in the value.
+var declarations = [
+  "content: url(",
+  "content: url( ",
+  "content: url(http://www.foo.com",
+  "content: url('http://www.foo.com'",
+  "background-image: -moz-linear-gradient(",
+  "background-image: -moz-linear-gradient( ",
+  "background-image: -moz-linear-gradient(red, blue",
+  "background-image: -moz-linear-gradient(red, yellow, blue",
+  "background-image: -moz-linear-gradient(red 1px, yellow 5px, blue 10px",
+  "background-image: -moz-linear-gradient(red, yellow, rgb(0, 0, 255)",
+  "background-image: -moz-repeating-linear-gradient(top left, red, blue",
+  "background-image: -moz-linear-gradient(top left, red, yellow, blue",
+  "background-image: -moz-linear-gradient(top left, red 1px, yellow 5px, blue 10px",
+  "background-image: -moz-linear-gradient(top left, red, yellow, rgb(0, 0, 255)",
+  "background-image: -moz-radial-gradient(",
+  "background-image: -moz-radial-gradient( ",
+  "background-image: -moz-radial-gradient(top left 45deg, red, blue",
+  "background-image: -moz-radial-gradient(cover, red, blue",
+  "background-image: -moz-repeating-radial-gradient(circle, red, blue",
+  "background-image: -moz-radial-gradient(ellipse closest-corner, red, hsl(240, 50%, 50%)",
+  "background-image: -moz-radial-gradient(farthest-side circle, red, blue",
+  "background-image: -moz-image-rect(",
+  "background-image: -moz-image-rect( ",
+  "background-image: -moz-image-rect(url(foo.jpg)",
+  "background-image: -moz-image-rect(url(foo.jpg), 2, 10, 10",
+  "background-image: -moz-image-rect(url(foo.jpg), 2, 10, 10 ",
+  "background-image: -moz-image-rect(url(foo.jpg), 2, 10, 10,",
+  "background-image: -moz-image-rect(url(foo.jpg), 2, 10, 10, ",
+  "background-image: -moz-image-rect(url(foo.jpg), 2, 10, 10, 10",
+  "background-image: -moz-image-rect(url(foo.jpg), 2, 10, 10, 10 ",
+  "background-image: -moz-image-rect(url(foo.jpg), 2, 10, 10, 10,",
+  "background-image: -moz-image-rect(url(foo.jpg), 2, 10, 10, 10, ",
+  "color: rgb(",
+  "color: rgb( ",
+  "color: rgb(128, 0",
+  "color: rgb(128, 0, 128",
+  "color: rgb(128, 0, 128, 128",
+  "color: rgba(",
+  "color: rgba( ",
+  "color: rgba(128, 0",
+  "color: rgba(128, 0, 128",
+  "color: rgba(128, 0, 128, 1",
+  "color: rgba(128, 0, 128, 1, 1",
+  "color: hsl(",
+  "color: hsl( ",
+  "color: hsl(240, 50%",
+  "color: hsl(240, 50%, 50%",
+  "color: hsl(240, 50%, 50%, 50%",
+  "color: hsla(",
+  "color: hsla( ",
+  "color: hsla(240, 50%",
+  "color: hsla(240, 50%, 50%",
+  "color: hsla(240, 50%, 50%, 1",
+  "color: hsla(240, 50%, 50%, 1, 1",
+  "content: counter(",
+  "content: counter( ",
+  "content: counter(foo",
+  "content: counter(foo ",
+  "content: counter(foo,",
+  "content: counter(foo, ",
+  "content: counter(foo, upper-roman",
+  "content: counter(foo, upper-roman ",
+  "content: counter(foo, upper-roman,",
+  "content: counter(foo, upper-roman, ",
+  "content: counters(",
+  "content: counters( ",
+  "content: counters(foo, ','",
+  "content: counters(foo, ',' ",
+  "content: counters(foo, ',',",
+  "content: counters(foo, ',', ",
+  "content: counters(foo, ',', upper-roman",
+  "content: counters(foo, ',', upper-roman ",
+  "content: counters(foo, ',', upper-roman,",
+  "content: counters(foo, ',', upper-roman, ",
+  "content: attr(",
+  "content: attr( ",
+  "content: attr(href",
+  "content: attr(href ",
+  "content: attr(html",
+  "content: attr(html ",
+  "content: attr(html|",
+  "content: attr(html| ",
+  "content: attr(html|href",
+  "content: attr(html|href ",
+  "content: attr(|",
+  "content: attr(| ",
+  "content: attr(|href",
+  "content: attr(|href ",
+  "-moz-transition-timing-function: cubic-bezier(",
+  "-moz-transition-timing-function: cubic-bezier( ",
+  "-moz-transition-timing-function: cubic-bezier(0, 0, 1",
+  "-moz-transition-timing-function: cubic-bezier(0, 0, 1 ",
+  "-moz-transition-timing-function: cubic-bezier(0, 0, 1,",
+  "-moz-transition-timing-function: cubic-bezier(0, 0, 1, ",
+  "-moz-transition-timing-function: cubic-bezier(0, 0, 1, 1",
+  "-moz-transition-timing-function: cubic-bezier(0, 0, 1, 1 ",
+  "-moz-transition-timing-function: cubic-bezier(0, 0, 1, 1,",
+  "-moz-transition-timing-function: cubic-bezier(0, 0, 1, 1, ",
+  "border-top-width: -moz-calc(",
+  "border-top-width: -moz-calc( ",
+  "border-top-width: -moz-calc(2em",
+  "border-top-width: -moz-calc(2em ",
+  "border-top-width: -moz-calc(2em +",
+  "border-top-width: -moz-calc(2em + ",
+  "border-top-width: -moz-calc(2em *",
+  "border-top-width: -moz-calc(2em * ",
+  "border-top-width: -moz-calc((2em)",
+  "border-top-width: -moz-calc((2em) ",
+];
+
+var textNode = document.createTextNode("");
+document.getElementById("style").appendChild(textNode);
+var cs = getComputedStyle(document.getElementById("display"), "");
+
+for (var i = 0; i < declarations.length; ++i) {
+  var sheet = "@namespace html url(http://www.w3.org/1999/xhtml);\n" +
+              "#display { color: green; " + declarations[i] +
+              " x x x x x x x ; color: red; ) ; z-index: " + (i + 1) + " }";
+  textNode.data = sheet;
+  is(cs.color, "rgb(0, 128, 0)",
+     "color for declaration '" + declarations[i] + "'");
+  is(cs.zIndex, i+1,
+     "z-index for declaration '" + declarations[i] + "'");
+}
+
+</script>
+</pre>
+</body>
+</html>