The infamous "SyntaxError on line 30" that happens on IE 9 & 10 happens only when Yeti is used on port 80. This doesn't happen during testing, since Yeti is tested on port 9000 for real browsers and random ports in automation.
Stopping early on this error makes it difficult to resolve a few YUI issues:
The error is caused by code in SockJS that essentially does:
var ws = new WebSocket("ws://yeti.yuilibrary.com:/tower/930/rnd0m/websocket");
It seems to include the colon : when it's not needed. IE doesn't like that.
Omit port from SockJS URL if not available. GH-46.
The document.location.port may be the empty string on IE
when a default port is being used. In that case, avoid
putting a port, or colon, in the URL to prevent a SyntaxError
during WebSocket construction.
Fixed in Yeti 0.2.23.