According to rfc4329, http://tools.ietf.org/html/rfc4329#page-10, javascript should have mime-type 'application/javascript' instead of 'application/x-javascript'. But currently, it seems we all use the latter one. grep the Source dir: Source/WebKit/qt/tests/qwebpage/tst_qwebpage.cpp: { "js", "application/x-javascript" }, Source/WebCore/loader/cache/CachedScript.cpp: // and refuse to serve them if we only accept application/x-javascript. Source/WebCore/platform/brew/MIMETypeRegistryBrew.cpp: { "js", "application/x-javascript" }, Source/WebCore/platform/MIMETypeRegistry.cpp: Mozilla 1.8 accepts application/javascript, application/ecmascript, and application/x-javascript, but WinIE 7 doesn't. Source/WebCore/platform/MIMETypeRegistry.cpp: "application/x-javascript", Source/WebCore/platform/wince/MIMETypeRegistryWinCE.cpp: mimetypeMap.add("js", "application/x-javascript"); Source/WebCore/platform/efl/MIMETypeRegistryEfl.cpp: { "js", "application/x-javascript" }, Source/WebCore/platform/gtk/MIMETypeRegistryGtk.cpp: { "js", "application/x-javascript" }, Source/WebCore/platform/wx/MimeTypeRegistryWx.cpp: { "js", "application/x-javascript" }, Source/WebCore/platform/haiku/MIMETypeRegistryHaiku.cpp: { "js", "application/x-javascript" }, Source/WebCore/platform/qt/MIMETypeRegistryQt.cpp: { "js", "application/x-javascript" }, Source/WebCore/platform/win/MIMETypeRegistryWin.cpp: mimetypeMap.add("js", "application/x-javascript"); Source/WebKit/chromium/webkit/glue/mimetype_unittest.cc: "application/x-javascript", Source/WebKit/chromium/net/base/mime_util.cc: { "application/x-javascript", "js" }, Source/WebKit/chromium/net/base/mime_util.cc:// application/x-javascript, but WinIE 7 doesn't. Source/WebKit/chromium/net/base/mime_util.cc: "application/x-javascript", Source/WebKit/chromium/net/proxy/proxy_script_fetcher_impl.cc: "application/x-javascript-config", Source/WebKit/chromium/third_party/mongoose/mongoose.c: {".js", 3, "application/x-javascript", 24}, And layout test fast/preloader/scan-body-from-head-script.html can comfirm this. It seems only chromium-linux has rebaselined this. LayoutTests/platform/chromium-linux/fast/preloader/script-expected.txt:script1.js has MIME type application/javascript LayoutTests/platform/chromium-linux/fast/preloader/scan-body-from-head-script-expected.txt:script1.js has MIME type application/javascript
Only references: https://searchfox.org/wubkat/rev/c67bb750f2c1083399f0dbe7d08b416cd45eee34/Source/WebCore/platform/MIMETypeRegistry.cpp#181 Which is coming from: https://mimesniff.spec.whatwg.org/#javascript-mime-type Two more for platform specific MIME: https://searchfox.org/wubkat/rev/c67bb750f2c1083399f0dbe7d08b416cd45eee34/Source/WebCore/platform/playstation/MIMETypeRegistryPlayStation.cpp#42 and https://searchfox.org/wubkat/rev/c67bb750f2c1083399f0dbe7d08b416cd45eee34/Source/WebCore/platform/win/MIMETypeRegistryWin.cpp#85 ___ Rest is in API Test. Although we do have few Layout Tests using this. @Anne - anything to do here or we can mark this as 'RESOLVED CONFIGURATION CHANGED'.
Platforms might want to map .js to text/javascript these days.