diff --git a/js/src/jit-test/tests/debug/Source-elementProperty.js b/js/src/jit-test/tests/debug/Source-elementProperty.js
new file mode 100644
index 000000000000..8201fc3025c0
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Source-elementProperty.js
@@ -0,0 +1,11 @@
+// Source.prototype.elementProperty can be a string or undefined.
+
+var g = newGlobal('new-compartment');
+var dbg = new Debugger;
+var gw = dbg.addDebuggee(g);
+g.evaluate("function f(x) { return 2*x; }", {elementProperty: "src"});
+var fw = gw.getOwnPropertyDescriptor('f').value;
+assertEq(fw.script.source.elementProperty, "src");
+g.evaluate("function f(x) { return 2*x; }");
+var fw = gw.getOwnPropertyDescriptor('f').value;
+assertEq(fw.script.source.elementProperty, undefined);
diff --git a/js/src/jit-test/tests/debug/Source-surfaces.js b/js/src/jit-test/tests/debug/Source-surfaces.js
index 969c076bea11..5f34770d59e4 100644
--- a/js/src/jit-test/tests/debug/Source-surfaces.js
+++ b/js/src/jit-test/tests/debug/Source-surfaces.js
@@ -21,3 +21,13 @@ assertThrowsInstanceOf(function () {
 assertThrowsInstanceOf(function () {
     Debugger.Source.prototype.element.call(Debugger.Source.prototype)
 }, TypeError);
+
+assertThrowsInstanceOf(function () {
+    Debugger.Source.prototype.elementProperty.call(42)
+}, TypeError);
+assertThrowsInstanceOf(function () {
+    Debugger.Source.prototype.elementProperty.call({})
+}, TypeError);
+assertThrowsInstanceOf(function () {
+    Debugger.Source.prototype.elementProperty.call(Debugger.Source.prototype)
+}, TypeError);
diff --git a/js/src/jsscript.cpp b/js/src/jsscript.cpp
index 137c7b5f4d5c..4d0a7c2338e7 100644
--- a/js/src/jsscript.cpp
+++ b/js/src/jsscript.cpp
@@ -970,6 +970,14 @@ ScriptSourceObject::element() const
     return getReservedSlot(ELEMENT_SLOT).toObjectOrNull();
 }
 
+const Value &
+ScriptSourceObject::elementProperty() const
+{
+    const Value &prop = getReservedSlot(ELEMENT_PROPERTY_SLOT);
+    JS_ASSERT(prop.isUndefined() || prop.isString());
+    return prop;
+}
+
 void
 ScriptSourceObject::finalize(FreeOp *fop, JSObject *obj)
 {
@@ -979,7 +987,8 @@ ScriptSourceObject::finalize(FreeOp *fop, JSObject *obj)
 
 const Class ScriptSourceObject::class_ = {
     "ScriptSource",
-    JSCLASS_HAS_RESERVED_SLOTS(2) | JSCLASS_IMPLEMENTS_BARRIERS | JSCLASS_IS_ANONYMOUS,
+    JSCLASS_HAS_RESERVED_SLOTS(RESERVED_SLOTS) |
+    JSCLASS_IMPLEMENTS_BARRIERS | JSCLASS_IS_ANONYMOUS,
     JS_PropertyStub,        /* addProperty */
     JS_DeletePropertyStub,  /* delProperty */
     JS_PropertyStub,        /* getProperty */
@@ -998,9 +1007,15 @@ ScriptSourceObject::create(ExclusiveContext *cx, ScriptSource *source,
     if (!object)
         return nullptr;
     RootedScriptSource sourceObject(cx, &object->as<ScriptSourceObject>());
+
     source->incref();
     sourceObject->initSlot(SOURCE_SLOT, PrivateValue(source));
     sourceObject->initSlot(ELEMENT_SLOT, ObjectOrNullValue(options.element()));
+    if (options.elementProperty())
+        sourceObject->initSlot(ELEMENT_PROPERTY_SLOT, StringValue(options.elementProperty()));
+    else
+        sourceObject->initSlot(ELEMENT_PROPERTY_SLOT, UndefinedValue());
+
     return sourceObject;
 }
 
diff --git a/js/src/jsscript.h b/js/src/jsscript.h
index dc9215ffa5ec..82f25a291085 100644
--- a/js/src/jsscript.h
+++ b/js/src/jsscript.h
@@ -465,10 +465,13 @@ class ScriptSourceObject : public JSObject
     void setSource(ScriptSource *source);
 
     JSObject *element() const;
+    const Value &elementProperty() const;
 
   private:
     static const uint32_t SOURCE_SLOT = 0;
     static const uint32_t ELEMENT_SLOT = 1;
+    static const uint32_t ELEMENT_PROPERTY_SLOT = 2;
+    static const uint32_t RESERVED_SLOTS = 3;
 };
 
 enum GeneratorKind { NotGenerator, LegacyGenerator, StarGenerator };
diff --git a/js/src/shell/js.cpp b/js/src/shell/js.cpp
index 36a581a8a9e8..29992017ea7c 100644
--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -859,6 +859,7 @@ Evaluate(JSContext *cx, unsigned argc, jsval *vp)
     bool noScriptRval = false;
     const char *fileName = "@evaluate";
     RootedObject element(cx);
+    RootedString elementProperty(cx);
     JSAutoByteString fileNameBytes;
     RootedString sourceURL(cx);
     RootedString sourceMapURL(cx);
@@ -910,6 +911,14 @@ Evaluate(JSContext *cx, unsigned argc, jsval *vp)
         if (v.isObject())
             element = &v.toObject();
 
+        if (!JS_GetProperty(cx, opts, "elementProperty", &v))
+            return false;
+        if (!v.isUndefined()) {
+            elementProperty = ToString(cx, v);
+            if (!elementProperty)
+                return false;
+        }
+
         if (!JS_GetProperty(cx, opts, "sourceURL", &v))
             return false;
         if (!v.isUndefined()) {
@@ -1012,6 +1021,7 @@ Evaluate(JSContext *cx, unsigned argc, jsval *vp)
             CompileOptions options(cx);
             options.setFileAndLine(fileName, lineNumber)
                    .setElement(element)
+                   .setElementProperty(elementProperty)
                    .setSourcePolicy(sourcePolicy)
                    .setCompileAndGo(compileAndGo);
 
@@ -3989,6 +3999,9 @@ static const JSFunctionSpecWithHelp shell_functions[] = {
 "         the source as being attached to the DOM element |o|. If the\n"
 "         property is omitted or |v| is null, don't attribute the source to\n"
 "         any DOM element.\n"
+"      elementProperty: if present and not undefined, the name of property\n"
+"         of 'element' that holds this code. This is what Debugger.Source\n"
+"         .prototype.elementProperty returns.\n"
 "      sourceMapURL: if present with value |v|, convert |v| to a string, and\n"
 "         provide that as the code's source map URL. If omitted, attach no\n"
 "         source map URL to the code (although the code may provide one itself,\n"
diff --git a/js/src/vm/Debugger.cpp b/js/src/vm/Debugger.cpp
index e54b951f6c0c..cf685aef9867 100644
--- a/js/src/vm/Debugger.cpp
+++ b/js/src/vm/Debugger.cpp
@@ -3785,12 +3785,20 @@ DebuggerSource_getElement(JSContext *cx, unsigned argc, Value *vp)
     return true;
 }
 
+static bool
+DebuggerSource_getElementProperty(JSContext *cx, unsigned argc, Value *vp)
+{
+    THIS_DEBUGSOURCE_REFERENT(cx, argc, vp, "(get elementProperty)", args, obj, sourceObject);
+    args.rval().set(sourceObject->elementProperty());
+    return Debugger::fromChildJSObject(obj)->wrapDebuggeeValue(cx, args.rval());
+}
 
 static const JSPropertySpec DebuggerSource_properties[] = {
     JS_PSG("text", DebuggerSource_getText, 0),
     JS_PSG("url", DebuggerSource_getUrl, 0),
     JS_PSG("element", DebuggerSource_getElement, 0),
     JS_PSG("displayURL", DebuggerSource_getDisplayURL, 0),
+    JS_PSG("elementProperty", DebuggerSource_getElementProperty, 0),
     JS_PS_END
 };