function checkstuff(daForm){
        // set these to the forwarded-to pages
        var allright = "378_io_al-mp1_5.1.1.htm";
        var somewrong = "378_io_al-mp1_5.1.2.htm";
        // total number of right answers
        var numright = 5;
        // some alert texts
        var alert_toofew = "Please select " + numright + " answers.";
        var alert_toomany = "Please select " + numright + " answers.";
        var alert_none = "Please select something.";
        
        // stuff below here should remain unchanged
        var numchecked = 0;
        var gotright = false;
        var gotwrong = false;
        for(i=0; i<daForm.elements.length; i++){
                daElem = daForm.elements[i];
                if(daElem.type == "check"){
                        if(daElem.checked){
                                numchecked++;
                                if(daElem.value){
                                        gotright = true;
                                }else{
                                        gotwrong = true;
                                }
                        }
                }
        }
        if(numchecked == numright && !gotwrong){
                // all right:
                document.location = allright;
        }else if(numchecked > numright){
                // too many checked:
                alert(alert_toomany);
        }if(numchecked > 0){
                // checked some
                if((gotright && !gotwrong) || (!gotright && gotwrong)){
                        // marked some right and none wrong or
                        // marked some wrong and none right
                        alert(alert_toofew);
                }else if(gotwrong && gotright){
                        // marked some right and some wrong
                        document.location = somewrong;
                }       
        }else{
                // marked none.
                alert(alert_none);
        }
}