I am a medical professional and use an electronic medical record website to submit electronic prescriptions. On this particular website, I keep getting automatic downloads of coupons that open up a PDF on my Mac. How do I stop the website from doing automatic downloads? I don't have this issue on other websites. In Chrome, I don't have this issue and only get the download if I specifically click on the coupon link. The website customer support said it's an issue with Firefox, not their website. How do I at least stop getting my Mac to open up downloaded PDFs automatically?