diff --git a/mozilla/js/rhino/src/org/mozilla/javascript/NativeNumber.java b/mozilla/js/rhino/src/org/mozilla/javascript/NativeNumber.java
index 50ff847e052..cd895871d1b 100644
--- a/mozilla/js/rhino/src/org/mozilla/javascript/NativeNumber.java
+++ b/mozilla/js/rhino/src/org/mozilla/javascript/NativeNumber.java
@@ -161,13 +161,44 @@ final class NativeNumber extends IdScriptableObject
             return num_to(value, args, DToA.DTOSTR_FIXED,
                           DToA.DTOSTR_FIXED, -20, 0);
 
-          case Id_toExponential:
-            return num_to(value, args, DToA.DTOSTR_STANDARD_EXPONENTIAL,
-                          DToA.DTOSTR_EXPONENTIAL, 0, 1);
+          case Id_toExponential: { 
+              // Handle special values before range check
+              if(Double.isNaN(value)) {
+                  return "NaN";
+              }
+              if(Double.isInfinite(value)) {
+                  if(value >= 0) {
+                      return "Infinity";
+                  }
+                  else {
+                      return "-Infinity";
+                  }
+              }
+              // General case
+              return num_to(value, args, DToA.DTOSTR_STANDARD_EXPONENTIAL,
+                      DToA.DTOSTR_EXPONENTIAL, 0, 1);
+          }
 
-          case Id_toPrecision:
-            return num_to(value, args, DToA.DTOSTR_STANDARD,
-                          DToA.DTOSTR_PRECISION, 1, 0);
+          case Id_toPrecision: {
+              // Undefined precision, fall back to ToString()
+              if(args.length == 0 || args[0] == Undefined.instance) {
+                  return ScriptRuntime.numberToString(value, 10);
+              }
+              // Handle special values before range check
+              if(Double.isNaN(value)) {
+                  return "NaN";
+              }
+              if(Double.isInfinite(value)) {
+                  if(value >= 0) {
+                      return "Infinity";
+                  }
+                  else {
+                      return "-Infinity";
+                  }
+              }
+              return num_to(value, args, DToA.DTOSTR_STANDARD,
+                      DToA.DTOSTR_PRECISION, 1, 0);
+          }
 
           default: throw new IllegalArgumentException(String.valueOf(id));
         }