2 files changed, 23 insertions, 2 deletions

diff --git a/README.md b/README.md
index 3245d404..04b0799e 100644
--- a/README.md
+++ b/README.md
@@ -628,6 +628,14 @@ console.log(result.code); // minified output
 console.log(result.map);
 ```
 
+To generate a source map with the fromString option, you can also use an object:
+```javascript
+var result = UglifyJS.minify({"file1.js": "var a = function () {};"}, {
+  outSourceMap: "out.js.map",
+  fromString: true
+});
+```
+
 Note that the source map is not saved in a file, it's just returned in
 `result.map`.  The value passed for `outSourceMap` is only used to set the
 `file` attribute in the source map (see [the spec][sm-spec]).
@@ -663,6 +671,17 @@ var result = UglifyJS.minify("compiled.js", {
 The `inSourceMap` is only used if you also request `outSourceMap` (it makes
 no sense otherwise).
 
+To set the source map url, use the `sourceMapUrl` option.
+If you're using the X-SourceMap header instead, you can just set the `sourceMapUrl` option to false.
+Defaults to outSourceMap:
+
+```javascript
+var result = UglifyJS.minify([ "file1.js" ], {
+  outSourceMap: "out.js.map",
+  sourceMapUrl: "localhost/out.js.map"
+});
+```
+
 Other options:
 
 - `warnings` (default `false`) — pass `true` to display compressor warnings.
diff --git a/tools/node.js b/tools/node.js
index 2ee7df21..20ecb473 100644
--- a/tools/node.js
+++ b/tools/node.js
@@ -43,6 +43,7 @@ exports.minify = function(files, options) {
         outSourceMap     : null,
         sourceRoot       : null,
         inSourceMap      : null,
+        sourceMapUrl     : null,
         fromString       : false,
         warnings         : false,
         mangle           : {},
@@ -136,8 +137,9 @@ exports.minify = function(files, options) {
     var stream = UglifyJS.OutputStream(output);
     toplevel.print(stream);
 
-    if (options.outSourceMap && "string" === typeof options.outSourceMap) {
-        stream += "\n//# sourceMappingURL=" + options.outSourceMap;
+    var mappingUrlPrefix = "\n//# sourceMappingURL=";
+    if (options.outSourceMap && typeof options.outSourceMap === "string" && options.sourceMapUrl !== false) {
+        stream += mappingUrlPrefix + (typeof options.sourceMapUrl === "string" ? options.sourceMapUrl : options.outSourceMap);
     }
 
     var source_map = output.source_map;