Pop-up ads or pop-ups are a form of online advertising on the World Wide Web intended to attract web traffic or capture email addresses. It works when certain web sites open a new web browser window to display advertisements. The pop-up window containing an advertisement's usually generated by JavaScript, but can be generated by other means as well. A variation on the pop-up window's the pop-under advertisement, which opens a new browser window hidden under the active window. Pop-unders don't… (More on Popup)