Is there a Dot-Probe Paradigm / visual-probe task available online? Is there an online resource to take the Dot-probe paradigm test>

When I searched I could only find a guide to set up a server for such a test. However, I don't have the ability to do that.

I'm specifically interested in a test that measures negativity/pessimism bias and tells you the results.
There appears to be an Inquisit implementation of the dot probe task that will run both online and in a lab. Such scripts can presumably be customised to your purposes. 

If you want to use this for research purposes, you would need to have access to a licence to Inquisit. 

There is also a trial version of the software. You could download the trial of Inquisit and the script and run the script on your computer.