The online weinre at http://debug-software.intel.com/ doesn't seem to work at the moment. The included script throws the following error:
on.displayName = func.displayName || func.name; return hookedFunction; };
I have tried the script in an "empty" app as well, to exclude any interference from my own code.
It's an otherwise excellent service that I use a lot!
There was an issue with the weinre client script at http://debug-software.intel.com/ getting corrupted on the way to the device, which caused the error you are seeing. I am now able to make weinre work from with the Simulate tab (as a quick test case) but I'm having trouble getting it to execute with App Preview. That may be related to my test app, please try it yourself. I also saw some odd CSP rule errors when I was trying this, that were being caused by the weinre client script on the device.
Another option is to use a remote weinre setup, see this doc for pointers on how to set that up > https://software.intel.com/en-us/xdk/docs/intel-xdk-debug-and-test-overview#WEINRE < it actually works better because there are minimal network lags due to having the weinre server running on your development machine on a local network.