I used :
http://myserver/file.php?xdebug_sesstion_start=1
and
http://myserver/file.php?DBGSESSID=1@clienthost:7869;d=1,p=1

and nothing happened!! the browser -IE- just print the result of executing the php file ?!!
is there any configration must be done before using these commands on the browser?

seems you didn't install debugger module on your server.
If the server is not yours, you can't debug it.

i have installed the debugger and the server is mine,
but the browser doesn't breakpoint at any point when i use the previous commands inside the URL and it just view the results of my php file.i did everything as u said before.
i install the server on another pc and i debug my code on it,not on my local pc where i start the browser.
how can i make the browser breakpoint ?

make sure that phpinfo displays DBG section and debugger is shown ENABLED there.