How to monitor the correctness of the rendering of the JS widgets on the site?

There was a problem to monitor the fact of rendering of widgets third-party services. Subscription form, payment widgets, stuff like Yandex.Posters - that is the whole JS is loaded from another server, but rendered on the client browser?

For example, on their sites you can hang JS-events and legerity them on the big traffic it important to track triggers, the goals in the metrics. And how to check that is drawn and trigger external services? For example, traffic is small, but very expensive. For example, an event that only happens once a day, but its value is incredibly large.
March 23rd 20 at 19:01
3 answers
March 23rd 20 at 19:03
for its facilities you can hang JS-events and their legerity

Well, external scripts also possible, just the things you need to delegate.
March 23rd 20 at 19:05
If the scripts directly to the page loaded - and work with your dom, you can do the same for their facilities. If in an iframe in the General case little can be done if the external scripts as yourself, then you will not report it.

If you need to do in terms of the test you in a controlled environment, there are tools that make a screenshot and compare with what it should be, maybe something happens with them.
March 23rd 20 at 19:07
There are a variety of services for logging errors.
One of the easiest to install is There are plohoi free rate 5000 logs per month. Anything above that quota - for a fee.

It classifies all errors, including those that arise from the client - for example using the extension some Google translator.
As an example, such as an error that the user has expired, the token threw him out of the Cabinet:

In General, the joke is convenient, but the Internet is infa that can affect proizvoditelnosti site\application.
We yuzaem in CRM written in reacte and we have the whole summer (the first rendering with the cache disabled):

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