diff -ur a/Makefile.PL b/Makefile.PL
--- a/Makefile.PL	2010-05-29 02:43:06.000000000 -0400
+++ b/Makefile.PL	2012-10-10 16:14:34.000000000 -0400
@@ -28,6 +28,8 @@
   libjs.a
   js32.dll
   libmozjs.so
+  libmozjs185.so
+  libmozjs187.so
 );
 
 my %possible_install_paths = (
diff -ur a/SpiderMonkey.pm b/SpiderMonkey.pm
--- a/SpiderMonkey.pm	2010-05-29 02:49:31.000000000 -0400
+++ b/SpiderMonkey.pm	2012-10-10 16:13:43.000000000 -0400
@@ -161,9 +161,8 @@
     $self->{global_class} = 
         JavaScript::SpiderMonkey::JS_GlobalClass();
     $self->{global_object} = 
-        JavaScript::SpiderMonkey::JS_NewObject(
-            $self->{context}, $self->{global_class}, 
-            $self->{global_class}, $self->{global_class});
+        JavaScript::SpiderMonkey::JS_NewCompartmentAndGlobalObject(
+            $self->{context}, $self->{global_class}); 
 
     JavaScript::SpiderMonkey::JS_InitStandardClasses($self->{context}, 
                                                      $self->{global_object});
diff -ur a/SpiderMonkey.xs b/SpiderMonkey.xs
--- a/SpiderMonkey.xs	2010-05-29 02:49:31.000000000 -0400
+++ b/SpiderMonkey.xs	2012-10-10 16:13:41.000000000 -0400
@@ -20,10 +20,13 @@
 #define snprintf _snprintf 
 #endif
 
+#ifndef JSCLASS_GLOBAL_FLAGS
+#define JSCLASS_GLOBAL_FLAGS 0
+#endif
 /* JSRuntime needs this global class */
 static
 JSClass global_class = {
-    "Global", 0,
+    "Global", JSCLASS_GLOBAL_FLAGS,
     JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,
     JS_EnumerateStub, JS_ResolveStub,   JS_ConvertStub,   JS_FinalizeStub
 };
@@ -67,10 +70,18 @@
          * I hope all reasonable machines can hold an address in
          * an int.
          */
-    XPUSHs(sv_2mortal(newSViv((int)obj)));
+    XPUSHs(sv_2mortal(newSViv(PTR2IV(obj))));
+#if JS_VERSION < 185
     XPUSHs(sv_2mortal(newSVpv(JS_GetStringBytes(JSVAL_TO_STRING(id)), 0)));
+#else
+    XPUSHs(sv_2mortal(newSVpv(JS_EncodeString(cx, JSVAL_TO_STRING(id)), 0)));
+#endif
     XPUSHs(sv_2mortal(newSVpv(what, 0)));
+#if JS_VERSION < 185
     XPUSHs(sv_2mortal(newSVpv(JS_GetStringBytes(JSVAL_TO_STRING(*vp)), 0)));
+#else
+    XPUSHs(sv_2mortal(newSVpv(JS_EncodeString(cx, JSVAL_TO_STRING(*vp)), 0)));
+#endif
     PUTBACK;
     call_pv("JavaScript::SpiderMonkey::getsetter_dispatcher", G_DISCARD);
     FREETMPS;
@@ -83,10 +94,21 @@
 JSBool getter_dispatcher(
     JSContext *cx, 
     JSObject  *obj,
+#if JS_VERSION < 185
     jsval      id,
+#else
+    jsid       iid,
+#endif
     jsval     *vp
 /* --------------------------------------------------------------------- */
 ) {
+#if JS_VERSION >= 185
+    jsval id;
+    if (!JS_IdToValue(cx,iid,&id)) {
+        fprintf(stderr, "getter_dispatcher: JS_IdToValue failed.\n");
+	return JS_FALSE;
+    }
+#endif
     return getsetter_dispatcher(cx, obj, id, vp, "getter");
 }
 
@@ -94,10 +116,22 @@
 JSBool setter_dispatcher(
     JSContext *cx, 
     JSObject  *obj,
+#if JS_VERSION < 185
     jsval      id,
+#else
+    jsid       iid,
+    JSBool     strict,
+#endif
     jsval     *vp
 /* --------------------------------------------------------------------- */
 ) {
+#if JS_VERSION >= 185
+    jsval id;
+    if (!JS_IdToValue(cx,iid,&id)) {
+        fprintf(stderr, "setter_dispatcher: JS_IdToValue failed.\n");
+	return JS_FALSE;
+    }
+#endif
     return getsetter_dispatcher(cx, obj, id, vp, "setter");
 }
 
@@ -128,10 +162,19 @@
 
 /* --------------------------------------------------------------------- */
 static JSBool
+#if JS_VERSION < 185
 FunctionDispatcher(JSContext *cx, JSObject *obj, uintN argc, 
     jsval *argv, jsval *rval) {
+#else
+FunctionDispatcher(JSContext *cx, uintN argc, jsval *vp) {
+#endif
 /* --------------------------------------------------------------------- */
     dSP; 
+#if JS_VERSION >= 185
+    JSObject *obj = JS_THIS_OBJECT(cx,vp);
+    jsval *argv = JS_ARGV(cx,vp);
+    jsval rval;
+#endif
     SV          *sv;
     char        *n_jstr;
     int         n_jnum;
@@ -149,12 +192,20 @@
     ENTER ; 
     SAVETMPS ;
     PUSHMARK(SP);
-    XPUSHs(sv_2mortal(newSViv((int)obj)));
+    XPUSHs(sv_2mortal(newSViv(PTR2IV(obj))));
     XPUSHs(sv_2mortal(newSVpv(
-        JS_GetFunctionName(fun), 0)));
+#if JS_VERSION < 185
+        JS_GetStringBytes(JS_GetFunctionId(fun)), 0)));
+#else
+        JS_EncodeString(cx, JS_GetFunctionId(fun)), 0)));
+#endif
     for(i=0; i<argc; i++) {
         XPUSHs(sv_2mortal(newSVpv(
+#if JS_VERSION < 185
             JS_GetStringBytes(JS_ValueToString(cx, argv[i])), 0)));
+#else
+            JS_EncodeString(cx, JS_ValueToString(cx, argv[i])), 0)));
+#endif
     }
     PUTBACK;
     count = call_pv("JavaScript::SpiderMonkey::function_dispatcher", G_SCALAR);
@@ -174,7 +225,11 @@
 
             if(Debug)
                 fprintf(stderr, "DEBUG: %lx is a ref!\n", (long) sv);
-            *rval = OBJECT_TO_JSVAL(SvIV(SvRV(sv)));
+#if JS_VERSION < 185
+            *rval = OBJECT_TO_JSVAL(INT2PTR(JSObject *,SvIV(SvRV(sv))));
+#else
+            JS_SET_RVAL(cx,vp,OBJECT_TO_JSVAL(INT2PTR(JSObject *,SvIV(SvRV(sv)))));
+#endif
         }
         else if(SvIOK(sv)) {
             /* It appears that we have been sent an int return
@@ -183,7 +238,11 @@
             n_jnum=SvIV(sv);
             if(Debug)
                 fprintf(stderr, "DEBUG: %lx is an int (%d)\n", (long) sv,n_jnum);
+#if JS_VERSION < 185
             *rval = INT_TO_JSVAL(n_jnum);
+#else
+            JS_SET_RVAL(cx,vp,INT_TO_JSVAL(n_jnum));
+#endif
         } else if(SvNOK(sv)) {
             /* It appears that we have been sent an double return
              * value.  Thats fine we can give javascript an double
@@ -192,11 +251,20 @@
 
             if(Debug) 
                 fprintf(stderr, "DEBUG: %lx is a double(%f)\n", (long) sv,n_jdbl);
+#if JS_VERSION < 185
             *rval = DOUBLE_TO_JSVAL(JS_NewDouble(cx, n_jdbl));
+#else
+            JS_NewNumberValue(cx, n_jdbl, &rval);
+            JS_SET_RVAL(cx,vp,rval);
+#endif
         } else if(SvPOK(sv)) {
             n_jstr = SvPV(sv, PL_na);
             //warn("DEBUG: %s (%d)\n", n_jstr);
+#if JS_VERSION < 185
             *rval = STRING_TO_JSVAL(JS_NewStringCopyZ(cx, n_jstr));
+#else
+            JS_SET_RVAL(cx,vp,STRING_TO_JSVAL(JS_NewStringCopyZ(cx, n_jstr)));
+#endif
         }
     }
 
@@ -240,8 +308,13 @@
 }
 
 /* --------------------------------------------------------------------- */
+#if JS_VERSION < 181
 static JSBool
 BranchHandler(JSContext *cx, JSScript *script) {
+#else
+static JSBool
+BranchHandler(JSContext *cx) {
+#endif
 /* --------------------------------------------------------------------- */
   PJS_Context* pcx = (PJS_Context*) JS_GetContextPrivate(cx);
 
@@ -374,11 +447,46 @@
     JSObject *obj;
     CODE:
     {
+#ifdef JS_THREADSAFE
+        JS_BeginRequest(cx);
+#endif
         obj = JS_NewObject(cx, class, NULL, NULL);
         if(!obj) {
             XSRETURN_UNDEF;
         }
         RETVAL = obj;
+#ifdef JS_THREADSAFE
+        JS_EndRequest(cx);
+#endif
+    }
+    OUTPUT:
+    RETVAL
+
+######################################################################
+JSObject *
+JS_NewCompartmentAndGlobalObject(cx, class)
+    JSContext * cx
+    JSClass   * class
+######################################################################
+    PREINIT:
+    JSObject *obj;
+    CODE:
+    {
+#ifdef JS_THREADSAFE
+        JS_BeginRequest(cx);
+#endif
+#if JS_VERSION < 185
+        obj = JS_NewObject(cx, class, NULL, NULL);
+#else
+        obj = JS_NewCompartmentAndGlobalObject(cx, class, NULL);
+#endif
+        if(!obj) {
+            XSRETURN_UNDEF;
+        }
+        RETVAL = obj;
+#ifdef JS_THREADSAFE
+        JS_EndRequest(cx);
+#endif
     }
     OUTPUT:
     RETVAL
@@ -404,6 +512,9 @@
     na = (uintN) nargs;
     CODE:
     {
+#ifdef JS_THREADSAFE
+        JS_BeginRequest(cx);
+#endif
         obj = JS_InitClass(cx, iobj, parent_proto, clasp,
                            constructor, nargs, ps, fs, static_ps,
                            static_fs);
@@ -411,6 +522,9 @@
             XSRETURN_UNDEF;
         }
         RETVAL = obj;
+#ifdef JS_THREADSAFE
+        JS_EndRequest(cx);
+#endif
     }
     OUTPUT:
     RETVAL
@@ -469,11 +583,17 @@
     JSBool rc;
     CODE:
     {
+#ifdef JS_THREADSAFE
+        JS_BeginRequest(cx);
+#endif
         rc = JS_InitStandardClasses(cx, gobj);
         if(!rc) {
             XSRETURN_UNDEF;
         }
         RETVAL = (int) rc;
+#ifdef JS_THREADSAFE
+        JS_BeginRequest(cx);
+#endif
     }
     OUTPUT:
     RETVAL
@@ -582,10 +702,18 @@
         rc = JS_GetProperty(cx, obj, name, &vp);
         if(rc) {
             str = JS_ValueToString(cx, vp);
+#if JS_VERSION < 185
             if(strcmp(JS_GetStringBytes(str), "undefined") == 0) {
+#else
+            if(strcmp(JS_EncodeString(cx, str), "undefined") == 0) {
+#endif
                 sv = &PL_sv_undef;
             } else {
+#if JS_VERSION < 185
                 sv_setpv(sv, JS_GetStringBytes(str));
+#else
+                sv_setpv(sv, JS_EncodeString(cx, str));
+#endif
             }
         } else {
             sv = &PL_sv_undef;
@@ -675,10 +803,18 @@
         rc = JS_GetElement(cx, obj, idx, &vp);
         if(rc) {
             str = JS_ValueToString(cx, vp);
+#if JS_VERSION < 185
             if(strcmp(JS_GetStringBytes(str), "undefined") == 0) {
+#else
+            if(strcmp(JS_EncodeString(cx, str), "undefined") == 0) {
+#endif
                 sv = &PL_sv_undef;
             } else {
+#if JS_VERSION < 185
                 sv_setpv(sv, JS_GetStringBytes(str));
+#else
+                sv_setpv(sv, JS_EncodeString(cx, str));
+#endif
             }
         } else {
             sv = &PL_sv_undef;
@@ -718,7 +854,11 @@
         PJS_Context* pcx = (PJS_Context *) JS_GetContextPrivate(cx);
         pcx->branch_count = 0;
         pcx->branch_max = max_branch_operations;
+#if JS_VERSION < 181
         JS_SetBranchCallback(cx, BranchHandler);
+#else
+        JS_SetOperationCallback(cx, BranchHandler);
+#endif
     }
     OUTPUT:
 
--- a/t/error.t	2012-10-10 16:18:21.000000000 -0400
+++ b/t/error.t	2012-10-10 16:20:45.000000000 -0400
@@ -9,8 +9,8 @@
 $js1->init ();
 ok (!$js1->eval ($jscode1));
 ok ($@ !~ "\n");
-ok ($@ =~ "SyntaxError");
+ok ($@ =~ "SyntaxError" || $@ =~ "ReferenceError: invalid assignment left-hand side");
 #print "$@\n";
 my $jscode2 =<<EOF;
 var fruit = non_existant_function ();
 EOF