As a reduced test case: <html><head></head><body> <h1>IE event syntax</h1> <b>Press any key now</b> <script> function document.onkeydown() { alert("Key Down!"); } alert("It works!"); </script> </body></html> To repro, save the above content to an html file, open it, and press any key. IE works and will show an alert. FF, WebKit don't. IE supports a way to create event handlers like: function document.onkeydown() { alert("Key Down!"); } JavaScriptCore does not recognize it and it will stop processing after seeing the syntax above. We should support it if possible, it's being used in a lot of websites. The one I saw this happening is at http://www.ccb.com, top 3 bank in China. After login, one js file (https://ibsbjstar.ccb.com.cn/V5/js5/mainPage.js) contains above syntax which prevented it from being usable.
Created attachment 18688 [details] test case Same test, as an attachment.
These are not on track for standardization, Firefox don't support these, and I think neither Chrome nor Opera do either? Without interest from ECMA or wider browser support I don't think we'll want to adopt further proprietary and non-standard mechanisms, without a good reason. A good reasons to reopen this bug would be ECMA adoption, wider de-facto support, or a major web compatibility issue.
*** Bug 18531 has been marked as a duplicate of this bug. ***