diff --git a/js/src/jsdate.cpp b/js/src/jsdate.cpp
index 076bf63ce160..a2e30612d32c 100644
--- a/js/src/jsdate.cpp
+++ b/js/src/jsdate.cpp
@@ -3199,20 +3199,3 @@ js_DateGetMsecSinceEpoch(JSContext *cx, JSObject *obj)
     return obj->isDate() ? obj->getDateUTCTime().toNumber() : 0;
 }
 
-#ifdef JS_THREADSAFE
-#include "prinrval.h"
-
-JS_FRIEND_API(uint32_t)
-js_IntervalNow()
-{
-    return uint32_t(PR_IntervalToMilliseconds(PR_IntervalNow()));
-}
-
-#else /* !JS_THREADSAFE */
-
-JS_FRIEND_API(uint32_t)
-js_IntervalNow()
-{
-    return uint32_t(PRMJ_Now() / PRMJ_USEC_PER_MSEC);
-}
-#endif
diff --git a/js/src/jsdate.h b/js/src/jsdate.h
index cad6d0a9fb10..cf0f35e804c2 100644
--- a/js/src/jsdate.h
+++ b/js/src/jsdate.h
@@ -83,11 +83,6 @@ js_DateGetMinutes(JSContext *cx, JSObject* obj);
 extern JS_FRIEND_API(int)
 js_DateGetSeconds(JSContext *cx, JSObject* obj);
 
-typedef uint32_t JSIntervalTime;
-
-extern JS_FRIEND_API(JSIntervalTime)
-js_IntervalNow();
-
 /* Date constructor native. Exposed only so the JIT can know its address. */
 JSBool
 js_Date(JSContext *cx, unsigned argc, js::Value *vp);
diff --git a/js/src/shell/js.cpp b/js/src/shell/js.cpp
index bd656e00feca..f7649e6293f6 100644
--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -141,7 +141,7 @@ static PRLock *gWatchdogLock = NULL;
 static PRCondVar *gWatchdogWakeup = NULL;
 static PRThread *gWatchdogThread = NULL;
 static bool gWatchdogHasTimeout = false;
-static PRIntervalTime gWatchdogTimeout = 0;
+static int64_t gWatchdogTimeout = 0;
 
 static PRCondVar *gSleepWakeup = NULL;
 
@@ -302,7 +302,7 @@ GetLine(FILE *file, const char * prompt)
  * on timing.
  */
 struct JSShellContextData {
-    volatile JSIntervalTime startTime;
+    volatile int64_t startTime;
 };
 
 static JSShellContextData *
@@ -316,7 +316,7 @@ NewContextData()
                                calloc(sizeof(JSShellContextData), 1);
     if (!data)
         return NULL;
-    data->startTime = js_IntervalNow();
+    data->startTime = PRMJ_Now();
     return data;
 }
 
@@ -2790,12 +2790,11 @@ Resolver(JSContext *cx, unsigned argc, jsval *vp)
 
 /*
  * Check that t1 comes strictly before t2. The function correctly deals with
- * PRIntervalTime wrap-around between t2 and t1 assuming that t2 and t1 stays
- * within INT32_MAX from each other. We use MAX_TIMEOUT_INTERVAL to enforce
- * this restriction.
+ * wrap-around between t2 and t1 assuming that t2 and t1 stays within INT32_MAX
+ * from each other. We use MAX_TIMEOUT_INTERVAL to enforce this restriction.
  */
 static bool
-IsBefore(PRIntervalTime t1, PRIntervalTime t2)
+IsBefore(int64_t t1, int64_t t2)
 {
     return int32_t(t1 - t2) < 0;
 }
@@ -2803,7 +2802,7 @@ IsBefore(PRIntervalTime t1, PRIntervalTime t2)
 static JSBool
 Sleep_fn(JSContext *cx, unsigned argc, jsval *vp)
 {
-    PRIntervalTime t_ticks;
+    int64_t t_ticks;
 
     if (argc == 0) {
         t_ticks = 0;
@@ -2820,19 +2819,19 @@ Sleep_fn(JSContext *cx, unsigned argc, jsval *vp)
         }
         t_ticks = (t_secs <= 0.0)
                   ? 0
-                  : PRIntervalTime(PR_TicksPerSecond() * t_secs);
+                  : int64_t(PRMJ_USEC_PER_SEC * t_secs);
     }
     if (t_ticks == 0) {
         JS_YieldRequest(cx);
     } else {
         JSAutoSuspendRequest suspended(cx);
         PR_Lock(gWatchdogLock);
-        PRIntervalTime to_wakeup = PR_IntervalNow() + t_ticks;
+        int64_t to_wakeup = PRMJ_Now() + t_ticks;
         for (;;) {
             PR_WaitCondVar(gSleepWakeup, t_ticks);
             if (gCanceled)
                 break;
-            PRIntervalTime now = PR_IntervalNow();
+            int64_t now = PRMJ_Now();
             if (!IsBefore(now, to_wakeup))
                 break;
             t_ticks = to_wakeup - now;
@@ -2892,7 +2891,7 @@ WatchdogMain(void *arg)
 
     PR_Lock(gWatchdogLock);
     while (gWatchdogThread) {
-        PRIntervalTime now = PR_IntervalNow();
+         int64_t now = PRMJ_Now();
          if (gWatchdogHasTimeout && !IsBefore(now, gWatchdogTimeout)) {
             /*
              * The timeout has just expired. Trigger the operation callback
@@ -2906,9 +2905,9 @@ WatchdogMain(void *arg)
             /* Wake up any threads doing sleep. */
             PR_NotifyAllCondVar(gSleepWakeup);
         } else {
-            PRIntervalTime sleepDuration = gWatchdogHasTimeout
-                                           ? gWatchdogTimeout - now
-                                           : PR_INTERVAL_NO_TIMEOUT;
+            int64_t sleepDuration = gWatchdogHasTimeout
+                                    ? gWatchdogTimeout - now
+                                    : PR_INTERVAL_NO_TIMEOUT;
             DebugOnly<PRStatus> status =
                 PR_WaitCondVar(gWatchdogWakeup, sleepDuration);
             JS_ASSERT(status == PR_SUCCESS);
@@ -2927,8 +2926,8 @@ ScheduleWatchdog(JSRuntime *rt, double t)
         return true;
     }
 
-    PRIntervalTime interval = PRIntervalTime(ceil(t * PR_TicksPerSecond()));
-    PRIntervalTime timeout = PR_IntervalNow() + interval;
+    int64_t interval = int64_t(ceil(t * PRMJ_USEC_PER_SEC));
+    int64_t timeout = PRMJ_Now() + interval;
     PR_Lock(gWatchdogLock);
     if (!gWatchdogThread) {
         JS_ASSERT(!gWatchdogHasTimeout);
@@ -3081,7 +3080,7 @@ Elapsed(JSContext *cx, unsigned argc, jsval *vp)
         double d = 0.0;
         JSShellContextData *data = GetContextData(cx);
         if (data)
-            d = js_IntervalNow() - data->startTime;
+            d = PRMJ_Now() - data->startTime;
         return JS_NewNumberValue(cx, d, vp);
     }
     JS_ReportError(cx, "Wrong number of arguments");