Definition:
A pop-up is a window or overlay that appears during navigation to display information, request an action or present an offer. It may open as a new browser window or, as is common on current websites, as a modal dialog within the page itself.
It differs from a pop-under, which opens behind the active window. A pop-up covers some or all of the visible content, so it can attract attention but may also interrupt the user’s task. Advertising is a common application, although pop-ups are also used for notices, forms, confirmations and privacy controls.
Benefits of using pop-ups on a website
A pop-up can highlight a message without reserving permanent space for it on the page. It may help communicate an important condition, present a newsletter subscription, recover an incomplete action or display a promotion related to the content.
Its usefulness depends on timing, frequency, relevance and how easily it can be closed. A window displayed too early, repeated on every visit or difficult to dismiss can damage the user experience. It does not guarantee registrations or sales either: the intended action and its effects on the rest of the visit need to be measured.
What a pop-up is used for
Pop-ups can serve commercial and functional purposes. In a campaign, they may present a product, discount or call to action associated with online advertising. In other contexts, they confirm an operation, display a warning, request a login, enlarge an image or collect preferences.
They can be triggered when the page loads, after a time interval, following an interaction, on reaching a point in the content or after detecting an estimated exit intent. The mechanism should be accessible by keyboard, manage focus correctly, provide a visible close control and not hide essential information without an alternative.
Pop-up blockers
A pop-up blocker is a browser function or extension that prevents websites from opening particular new windows. Browsers commonly block automatic openings that are not connected to a user action and allow exceptions for specified websites.
This function is not exactly the same as an ad blocker. The first acts on pop-up windows, while the second may filter advertising requests, placements and resources in different formats. Modals integrated into a page’s HTML do not necessarily behave like new windows either and may require other control mechanisms.