he's tossing a bunch of link elements that are 0x0 px with an 8px border at your ship for you to click on. Only ones with addresses you've visited are visible:

he's tossing a bunch of link elements that are 0x0 px with an 8px border at your ship for you to click on. Only ones with addresses you've visited are visible: a:visited { background-color:pink;} Because you're clicking the border and not the element which is 0x0 you're not redirected but he knows the mouse position and from there can figure out which link you clicked on.