how can I read some data from any client connected a web server ?

You dont program your web server to find / get to the client - you program the other way round. Create a client, point it to the web server (web services / database connection / socket, whatever) and then fetch data from the server.

In your scenario, you might consider a duplex service as an option.

wrote:

there is a client(sender of information)and another client (receiver) actually I want to send sinosoidal signal from sender to receiver at the real time( at the time the sender begin transmission) without stocking this signal and send it again. therefore I have used the Netscape Navigator that takes a snapshot every 0.1s from the source and display the image at the receiver. so I think I need a server does that relation between the two client's. (Like server MSN but that time I want to send an image ) .

You have to use Ajax / Javascript remote scripting for sending and receiving data from the clients. But the server wont be able to keep any open connection which can send data as it comes in with your receiver client. Instead your receiver client has to ping the server in frequent interval and check for any available data.

thanks everyone, I am going to try something you advised me :confused:
wish me good luck :)