diff --git a/whalesong/js-assembler/runtime-src/baselib-primitives.js b/whalesong/js-assembler/runtime-src/baselib-primitives.js
index bf70cea..6df9911 100644
--- a/whalesong/js-assembler/runtime-src/baselib-primitives.js
+++ b/whalesong/js-assembler/runtime-src/baselib-primitives.js
@@ -3146,18 +3146,22 @@
 
 
 
-    // The default prompt handler consumes a thunk and applies it.
+    // The default abort prompt handler consumes a thunk and applies
+    // it, in a context where a new prompt has been initialized.
     var defaultPromptHandler = 
-        makeClosure("default-prompt-handler",
-                    1,
-                    function(M) {
-                        var proc = checkProcedure(M, 'apply', 0);
-                        M.e.pop();
-                        M.p = proc;
-                        M.a = 0;
-                        baselib.functions.rawApply(M);
-                    },
-                    []);
+        makeClosure(
+            "default-prompt-handler",
+            1,
+            function(M) {
+                var proc = checkProcedure(M, 'apply', 0);
+                M.e.pop();
+                M.p = proc;
+                M.a = 0;
+                M.addPrompt(baselib.contmarks.DEFAULT_CONTINUATION_PROMPT_TAG,
+                            false);
+                baselib.functions.rawApply(M);
+            },
+            []);
 
 
     installPrimitiveClosure(
diff --git a/whalesong/js-assembler/runtime-src/runtime.js b/whalesong/js-assembler/runtime-src/runtime.js
index 842e730..809b37c 100644
--- a/whalesong/js-assembler/runtime-src/runtime.js
+++ b/whalesong/js-assembler/runtime-src/runtime.js
@@ -488,6 +488,24 @@
         return new baselib.contmarks.ContinuationMarkSet(kvLists);
     };
 
+    
+    var justReturn = function(M) {
+        M.p=M.c[M.c.length-1].label;
+        M.c.pop();
+        return(M.p)(M);
+    };
+    justReturn.mvr = function(M) {
+        M.p=M.c[M.c.length-1].label;
+        M.c.pop();
+        return(M.p.mvr)(M);
+    };
+    Machine.prototype.addPrompt = function(promptTag, abortHandlerClosure) {
+        this.c.push(new PromptFrame(justReturn,
+                                    DEFAULT_CONTINUATION_PROMPT_TAG,
+                                    this.e.length,
+                                    abortHandlerClosure));
+    };
+