uncaught exception: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMNSHTMLInputElement.selectionStart]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: http://localhost:49342/sitename/ScriptResource.axd?d=32Ti6CiAhS6po2KfqwXvFtjIA-S1LSF8GXuojaB1782tzlcByVTmnCejff9ZYHCwnyA3buIvcHgcNU2jWJ2FPBMDQcdjkty8cPtJcoH-oJI1&t=ffffffff9e149c72 :: Sys$Serialization$JavaScriptSerializer$_serializeWithBuilder :: line 6275" data: no]

I finally figured it out. It helps if I tack on the ".value" when trying to reference the value of a text box. Still, it seems like a pretty ambiguous error, doesn't it?