Clickjacking is a computer technique fraudulent, detected for the first time in September 2008 by Robert Hansen and Jeremiah Grossman, which provides for the redirection to another object clicked, unbeknownst to the navigator.
During a normal web browsing, the user clicks with the mouse pointer, for example on an object link, or on elements internal to an email, but in reality its click is precisely hijacked without the user's knowledge, on another object.

Typically the vulnerability exploits JavaScript or Iframe and to defend against this threat, we must disable the execution of java script code inside the browser and also the execution of the Iframe, which is problematic ... the best thing to do is to avoid going to sites that we do not know!