function loin(bt) {
var email = prompt("Login (Registered email-id)","");
if(email!="")
{
	var enteredpassword = prompt("Password","");
	var password = "";
  	var last = 1;
  	for(var i=1;i<email.length;i=i+last)
  	{
   		password = password+email.charAt(i);
   		last = i;
  	}
  	if(password==enteredpassword)
  	{
  		switch(bt)
  		{
  			case 1:
 				window.open('ftp://ftp.umiacs.umd.edu/pub/agupta/4persons.zip','Download','width=400,height=200,left=0,top=100,screenX=0,screenY=100');
  				break;
  			case 2:
  			    window.open('ftp://ftp.umiacs.umd.edu/pub/agupta/10qfef_st.eps','Download','width=400,height=200,left=0,top=100,screenX=0,screenY=100');
  				break;
			case 3:
			    window.open('ftp://ftp.umiacs.umd.edu/pub/agupta/5persons.zip','Download','width=400,height=200,left=0,top=100,screenX=0,screenY=100');
  				break;
			case 4:
			    window.open('ftp://ftp.umiacs.umd.edu/pub/agupta/calibration.zip','Download','width=400,height=200,left=0,top=100,screenX=0,screenY=100');
  				break;
			case 5:
			    window.open('ftp://ftp.umiacs.umd.edu/pub/agupta/cvpr_2007_dataset.zip','Download','width=400,height=200,left=0,top=100,screenX=0,screenY=100');
				break;

  		}
  	}

}
}