function check_login(){
      var username = document.copage.credential_0;
      var pass = document.copage.credential_1;

      if (username && pass){
         	if (username.value == ""){
	    alert ('You must enter an e-mail address');
	username.focus();
  	} else if (pass.value == ""){
	    alert ('You must enter a password.');
	pass.focus();
  	} else {
	document.copage.submit();
  	}
    }
}