diff --git a/dom/bindings/test/Makefile.in b/dom/bindings/test/Makefile.in
index cb3c7ddb9f7..db9e997a867 100644
--- a/dom/bindings/test/Makefile.in
+++ b/dom/bindings/test/Makefile.in
@@ -58,6 +58,7 @@ $(CPPSRCS): ../%Binding.cpp: $(bindinggen_dependencies) \
 
 _TEST_FILES = \
   test_enums.html \
+  test_integers.html \
   test_interfaceToString.html \
   test_lookupGetter.html \
   test_InstanceOf.html \
diff --git a/dom/bindings/test/test_integers.html b/dom/bindings/test/test_integers.html
new file mode 100644
index 00000000000..1db0867ac2a
--- /dev/null
+++ b/dom/bindings/test/test_integers.html
@@ -0,0 +1,39 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none">
+  <canvas id="c" width="1" height="1"></canvas>
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+  function testInt64NonFinite(arg) {
+    // We can use a WebGLRenderingContext to test conversion to 64-bit signed
+    // ints edge cases.
+    var gl = $("c").getContext("experimental-webgl");
+    is(gl.getError(), 0, "Should not start in an error state");
+
+    var b = gl.createBuffer();
+    gl.bindBuffer(gl.ARRAY_BUFFER, b);
+
+    var a = new Float32Array(1);
+    gl.bufferData(gl.ARRAY_BUFFER, a, gl.STATIC_DRAW);
+
+    gl.bufferSubData(gl.ARRAY_BUFFER, arg, a);
+
+    is(gl.getError(), 0, "Should have treated non-finite double as 0");
+  }
+
+  testInt64NonFinite(NaN);
+  testInt64NonFinite(Infinity);
+  testInt64NonFinite(-Infinity);
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/src/xpcpublic.h b/js/xpconnect/src/xpcpublic.h
index 22d271ed6ee..3868963e16b 100644
--- a/js/xpconnect/src/xpcpublic.h
+++ b/js/xpconnect/src/xpcpublic.h
@@ -22,6 +22,7 @@
 #include "nsStringGlue.h"
 #include "nsTArray.h"
 #include "mozilla/dom/DOMJSClass.h"
+#include "nsMathUtils.h"
 
 class nsIPrincipal;
 class nsIXPConnectWrappedJS;
@@ -284,7 +285,12 @@ ValueToInt64(JSContext *cx, JS::Value v, int64_t *result)
         double doubleval;
         if (!JS_ValueToNumber(cx, v, &doubleval))
             return false;
-        *result = static_cast<int64_t>(doubleval);
+        // Be careful with non-finite doubles
+        if (NS_finite(doubleval))
+            // XXXbz this isn't quite right either; need to do the mod thing
+            *result = static_cast<int64_t>(doubleval);
+        else
+            *result = 0;
     }
     return true;
 }
@@ -304,7 +310,12 @@ ValueToUint64(JSContext *cx, JS::Value v, uint64_t *result)
         double doubleval;
         if (!JS_ValueToNumber(cx, v, &doubleval))
             return false;
-        *result = static_cast<uint64_t>(doubleval);
+        // Be careful with non-finite doubles
+        if (NS_finite(doubleval))
+            // XXXbz this isn't quite right either; need to do the mod thing
+            *result = static_cast<uint64_t>(doubleval);
+        else
+            *result = 0;
     }
     return true;
 }
