Your computer is used as long as you are on the AutoFaucet site. It is also possible that the site leaves its script in your browser cache or your computer memory. Thus, even if you are not on the AutoFaucet site, it might happen that your computer will mine Altcoins in the benefit of the site owner.
We would like to make you attentive that such mining scripts might contain Malware or Trojans. Microsoft has announced that its Windows Defender has blocked Malware and Trojans from such mining scripts on more than 400,000 computers in just one day.
If your computer is not powerful enough or a bit too old, the AutoFaucet mining script might damage your computer processor and / or graphic card.
Firefox has made available an extension called Mine Blocker that detects mining scripts.
It is very useful because there are sites that are not declared as AutoFaucet sites but, in background, they use your computer without informing on the site about this "feature".
It should be clear that the mining scripts perform Altcoins mining mainly in the owner benefit, not in yours.