function popupLogin(username, password) 
{
	// check to make sure a valid username has been entered

	var lang = "sl";

	// the size of the popup window
	var width = 800;
	var height = 600;

	// the x,y position of the popup window
	// NOTE: this formula will auto-center the popup on the screen
	var y = (screen.height - height) / 2;
	var x = (screen.width - width) / 2;

	var session_inst = 1;
	/*if(document.login.session_inst != undefined)
	{
		session_inst = document.login.session_inst.value;
	}*/

	var url ='http://forum.bradavicarka.si/chat/' + 'flashchat.php?username=' + username + '&password=' + password + '&lang=' + lang+'&session_inst='+session_inst;
	var options = 'width=' + width + ',height=' + height + ',top=' + y + ',left=' + x + ',resizable';

	// open the chat window as a popup, instead of embedded in webpage
	window.open( url, 'chat', options );
}