Website links work OK in Opera browser, not so in Safari

There's a website (or two) that I cannot log into using Safari because when I click on the 'login' button there is no response at all. But when I try the same using Opera browser it all works just fine.

This no-response symptom isn't just limited to login buttons. Often I find a website where clicking a link on the page does nothing when using Safari. I have to switch browsers in order to use that website & associated links.

Also, when I right-click on a link in Safari that does work, the top few options include 'Open Link in New Tab' and 'Open Link in New Window', etc. But the only link-related option listed for those that don't work is 'Copy Link'.

I'm at a loss as to the cause and was wondering if there are settings that might need to be changed so that all links will work in Safari?

I'm not a Mac expert (obviously) but I can find my way around pretty good. I'm currently running the latest version of Mavericks.

Thanks for any suggestions.

Hmm if only we knew the web sites?

Oops...one of the websites is Udemy.com, the login button in the upper right. There are other websites that I run across occasionally which I don't remember specifics just now. But they all act the same as the Udemy login website. And it doesn't seem to matter whether I am blocking pop-ups or not.

Opens just great t the courses login page.

I know that it should open for me, too. It doesn't and I was thinking it might be a setting in Preferences (or not) but I don't know what to look for that might be causing this. I'm open to suggestions. ��