function centerWin(w,h,url,n) {
	if(!window.opera){
		l	= (screen.availWidth/2)-(w/2);
		t	= (screen.availHeight/2)-(h/2);
    	 win	= window.open(url,n,"width="+w+",height="+h+",left="+l+",top="+t+"");
		win.focus();
	}
	else{
		/*opera*/
		l	= (window.innerWidth/2)-(w/2);
		t	= (window.innerHeight/2)-(h/2);
    	 win	= window.open(url,n,"width="+w+",height="+h+",left="+l+",top="+t+"");
		win.focus();
	}		
}