First-Class MailÂ® is a fast, affordable way to send envelopes and lightweight packages. Itâs perfect for business and personal correspondence, cards, brochures, and lightweight merchandise. The First-Class Mail ForeverÂ® Stamp price is $0.49; First-Class Mail Postcard Stamp price is $0.34.
Architecture of a metasearch engine. A metasearch engine (or aggregator) is a search tool that uses another search engine's data to produce their own results from the Internet. Metasearch engines take input from a user and simultaneously send out queries to third party search engines for results. Sufficient data is gathered, formatted by their ranks and presented to the users.
Abbreviated as XHR, XMLHttpRequest is a set of APIs that can be used by Web browser scripting languages, such as JavaScript to transfer XML and other text data to and from a Web server using HTTP. XMLHttpRequest works by establishing a communication channel between a Web page's client-side and server-side.