URI, URL and URN

URI : A URI "Uniform Resource Idetifier" can be further classified as a locator, a name, or both.

URL: The term "Uniform Resource Locator" (URL) refers to the subset of URIs that, in addition to identifying a resource, provide a means of locating the resource by describing its primary access mechanism (e.g., its network "location").

URN: The term "Uniform Resource Name" (URN) has been used historically to refer to both URIs under the "urn" scheme [RFC2141], which are required to remain globally unique name.

Clickjacking

On Clickjacked page the attacker load another page over it. The user think that they clicking visible button while they are actually performing actions on the hidden invisible page.

Clickjacking is known as "UI Redress Attack" , here attacker is hijacking user click for their page and routing them another page.

Example:

• Tricking users into making their social networking profile information public
• Making users follow someone on Twitter
• Sharing links on Facebook
• Getting likes on Facebook fan page
• Making illegal revenue from Google Adsense program

More practical example is when user going to play  movie after clicking on play button then sometime it redirect user in another link this is clickjacking.