HTTP Stands for Hypertext Transfer Protocol.
It is basically used to communicate web pages to web browsers,(HTTP) is used by web servers.When your browser connects to a web server, requests a web page from the server, and downloads the page,HTTP is used. It is a common standard that enables any browser to connect to any server, anywhere in the world.
HTTP was originally designed by Tim Berners-Lee to support the special demands of web communications and with an emphasis on efficiency, and a target page load time of under a tenth of a second. Modern Internet networks can support this type of response provided the page isn’t too large and the server is too far away.
To download different parts of a web page, downloading the text, graphics, and other objects on the page in different orders,your browser can open more than one HTTP connection at once. That is why you may see the status messages in the bottom of your browser window switch between a message like “downloading 38% of 47K” to “downloading 62% of 15K” on the same page — there are different HTTP connections.
To specify the download priorities,some browsers enable you so that, for example, graphics are not loaded, text is loaded before graphics, everything is loaded at once, etc and check your individual browser preferences
Reference : Dilip Kumar Jena ( https://mstechexplore.wordpress.com )