For a very quick port of KJS to Win32 from JavaScriptCore, here's the results: Test List: All tests Skip List: ecma/Date 967 test(s) selected, 962 test(s) completed, 319 failures reported (33.16% failed) Engine command line: testkjs.exe OS type: Testcase execution time: 7 minutes, 13 seconds. Tests completed on Fri Jun 10 21:17:47 2005. Most of that time was spent clicking Don't Send in the Watson error reporter. 131 regressions failed, so the rest (188) are crashes. When and where they crash, I don't know. But its my job to find out and bring Win32 JavaScriptCore in sync with OS X JavaScriptCore in stability.