diff --git a/build/test.js b/build/test.js
index 58b9ba7c..c83a3d1f 100644
--- a/build/test.js
+++ b/build/test.js
@@ -51,7 +51,9 @@ assert.equal('font/opentype', mime.lookup('file.otf'));
 //
 
 assert.equal('UTF-8', mime.charsets.lookup('text/plain'));
-assert.equal(undefined, mime.charsets.lookup(mime.types.js));
+assert.equal('UTF-8', mime.charsets.lookup(mime.types.js));
+assert.equal('UTF-8', mime.charsets.lookup(mime.types.json));
+assert.equal(undefined, mime.charsets.lookup(mime.types.xml));
 assert.equal('fallback', mime.charsets.lookup('application/octet-stream', 'fallback'));
 
 console.log('\nAll tests passed');
diff --git a/mime.js b/mime.js
index 341b6a5c..a401abf7 100644
--- a/mime.js
+++ b/mime.js
@@ -101,7 +101,7 @@ mime.Mime = Mime;
 mime.charsets = {
   lookup: function(mimeType, fallback) {
     // Assume text types are utf8
-    return (/^text\//).test(mimeType) ? 'UTF-8' : fallback;
+    return (/^text\/|^application\/(javascript|json)/).test(mimeType) ? 'UTF-8' : fallback;
   }
 };