Jsparsy will scan a set of URLs for javascript runtime errors, console.log() outputs, as well as server errors. It is capable of doing a full POST or GET login prior checking the given URLs.
casperjs jsparsy.js --config=/path/to/config.json --urls=/path/to/urls.json --server-errors=yes|no
See jsparsy.config.json-sample.
It is also possible and even recommended to use the configuration file from crawlpy, as you will need that anyway to generate the URL's (next section).
You can use crawlpy to generate the URL json file.