Help getting Loop to display properly

Hi there,

I have been working away at my understanding of Javascript, tried to give this forum a break, and came up with the following code. I am trying to display a list of required fields in a calculated field if they aren’t chosen by one of my 6 dropdown fields. I think I’m on the right track but nothing is displaying. Could I please have a hand?

(function(){
 var courses = [fieldname70,fieldname308,fieldname312,fieldname316,fieldname320,fieldname324],
     required = ['ENG4U','PSY4U','MAT4U','SCH4U'],
     msg = [],
     ret = 0,
     i;
 for(var i=0; i<courses.length; i++){
   ret |= 1 << sel[i].selectedIndex >> 1;
 }
 for(var i=0; i<required.length; i++){
  if(!(1<<i & ret)){
   msg.push(required[i]);
  }
 }
 if(msg.length == 0){
  msg = 'Everything achieved';
 } else if(msg.length == 1){
  msg = msg[0] + ' is missing';
 } else {
  msg = msg.slice(0, -1).join(', ') +' and '+ msg.pop() +' are missing';
 }
 return msg;
jQuery('#wes_civ').html(msg);
})()