I am having problems with my specific install. I am trying to trace the problems, but I thought I’d post what I’ve found so far here so that it may help others.
WordPress 3.6 upgraded by jQuery to 1.10.2, when I downgrade it back to jQuery 1.8.3 I have no problems.
The jquery form plugin (in Firefox 23.0.1) passes a complex form DOM component as the “method”. The plugin then attempts to convert this to upper case using toUpperCase. Because this is not a string, it fails.
In safari (7.0) ‘undefined’ is passed as the method which also doesn’t allow a toUpperCase() to be run on it.
When bypassing this function, It further passes components up to the jQuery root but not as strings which causes further breaks.
Again, putting jQuery 1.8.3 back in place seems to fix all issues related to Contact Form 7. However, I still have to see if that breaks anything anywhere else in the 3.6 install.
