diff --git a/content/svg/content/src/DOMSVGStringList.cpp b/content/svg/content/src/DOMSVGStringList.cpp
index 3c743c5dfd64..8fd2a53d605c 100644
--- a/content/svg/content/src/DOMSVGStringList.cpp
+++ b/content/svg/content/src/DOMSVGStringList.cpp
@@ -141,6 +141,9 @@ DOMSVGStringList::InsertItemBefore(const nsAString & newItem,
                                    PRUint32 index,
                                    nsAString & _retval)
 {
+  if (newItem.IsEmpty()) { // takes care of DOMStringIsNull too
+    return NS_ERROR_DOM_SVG_INVALID_VALUE_ERR;
+  }
   index = NS_MIN(index, InternalList().Length());
 
   // Ensure we have enough memory so we can avoid complex error handling below:
@@ -160,6 +163,9 @@ DOMSVGStringList::ReplaceItem(const nsAString & newItem,
                               PRUint32 index,
                               nsAString & _retval)
 {
+  if (newItem.IsEmpty()) { // takes care of DOMStringIsNull too
+    return NS_ERROR_DOM_SVG_INVALID_VALUE_ERR;
+  }
   if (index >= InternalList().Length()) {
     return NS_ERROR_DOM_INDEX_SIZE_ERR;
   }
diff --git a/content/svg/content/test/Makefile.in b/content/svg/content/test/Makefile.in
index 4d8c8ccbc590..0925d9de0b03 100644
--- a/content/svg/content/test/Makefile.in
+++ b/content/svg/content/test/Makefile.in
@@ -90,6 +90,7 @@ _TEST_FILES = \
 		test_SVGMatrix.xhtml \
 		test_SVGPathSegList.xhtml \
 		test_SVGStyleElement.xhtml \
+		test_SVGStringList.xhtml \
 		test_SVGTransformList.xhtml \
 		test_SVGTransformListAddition.xhtml \
 		test_SVGxxxList.xhtml \
diff --git a/content/svg/content/test/test_SVGStringList.xhtml b/content/svg/content/test/test_SVGStringList.xhtml
new file mode 100644
index 000000000000..e1847292f1c8
--- /dev/null
+++ b/content/svg/content/test/test_SVGStringList.xhtml
@@ -0,0 +1,119 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=724993-->
+<head>
+  <title>Tests specific to SVGStringList</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <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=724993">Mozilla Bug 724993</a>
+<p id="display"></p>
+<div id="content" style="display:none;">
+<svg id="svg" xmlns="http://www.w3.org/2000/svg" width="100" height="100">
+  <g id="g" requiredFeatures="foo bar baz"/>
+</svg>
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+
+/*
+This file runs a series of SVGStringList specific tests. Generic SVGXxxList
+tests can be found in test_SVGxxxList.xhtml. Anything that can be generalized
+to other list types belongs there.
+*/
+
+function initializeThrowsFor(stringList, value)
+{
+  try {
+    stringList.initialize(value);
+  } catch (e) {
+    return true;
+  }
+  return false;
+}
+
+function insertItemBeforeThrowsFor(stringList, value) 
+{  
+  try {
+    stringList.insertItemBefore(value, 0);
+  } catch (e) {
+    return true;
+  }
+  return false;
+}
+
+function replaceItemThrowsFor(stringList, value) 
+{  
+  try {
+    stringList.replaceItem(value, 0);
+  } catch (e) {
+    return true;
+  }
+  return false;
+}
+
+function appendItemThrowsFor(stringList, value) 
+{  
+  try {
+    stringList.appendItem(value);
+  } catch (e) {
+    return true;
+  }
+  return false;
+}
+
+function run_tests()
+{
+  var g = document.getElementById("g");
+  var strings = g.requiredFeatures;
+
+  // sanity check:
+  is(strings.numberOfItems, 3, 'numberOfItems should be 3');
+
+
+  ok(initializeThrowsFor(strings, null),
+     "SVGStringList.initialize() should throw when passed null");
+  ok(initializeThrowsFor(strings, ""),
+     "SVGStringList.initialize() should throw when passed the empty string");
+
+  ok(insertItemBeforeThrowsFor(strings, null),
+     "SVGStringList.insertItemBefore() should throw when passed null");
+  ok(insertItemBeforeThrowsFor(strings, ""),     
+     "SVGStringList.insertItemBefore() should throw when passed the empty string");
+
+  ok(replaceItemThrowsFor(strings, null),
+     "SVGStringList.replaceItem() should throw when passed null");
+  ok(replaceItemThrowsFor(strings, ""),     
+     "SVGStringList.replaceItem() should throw when passed the empty string");
+
+  ok(appendItemThrowsFor(strings, null),
+     "SVGStringList.appendItem() should throw when passed null");
+  ok(appendItemThrowsFor(strings, ""),     
+     "SVGStringList.appendItem() should throw when passed the empty string");
+
+
+  // more sanity checks:
+  ok(!initializeThrowsFor(strings, "valid-string"),
+     "SVGStringList.initialize() should not throw when passed a valid string");
+  ok(!insertItemBeforeThrowsFor(strings, "valid-string"),
+     "SVGStringList.insertItemBefore() should not throw when passed a valid string");
+  ok(!replaceItemThrowsFor(strings, "valid-string"),
+     "SVGStringList.replaceItem() should not throw when passed a valid string");
+  ok(!appendItemThrowsFor(strings, "valid-string"),
+     "SVGStringList.appendItem() should not throw when passed a valid string");
+  is(strings.length, 3, 'numberOfItems should be 3');
+
+  SimpleTest.finish();
+}
+
+window.addEventListener("load", run_tests, false);
+
+]]>
+</script>
+</pre>
+</body>
+</html>
