Developing a web based two player game in PHP

[Jack Hard]

I want to develop a simple game in PHP.Game is as follows, a server displays a image to the two players,two players have to type keyword corresponding to the image if the key word is same,they are given next image. What I am confused is how to develop the interface for this game.How do I display an image to two different players simultaneously and how do i keep track of their answers.Moreover how to implement two players ?