function insertInitialRows()
 {
  for (x=1;x<=5;x++) insertRow();
 }
 function showFirstColumn(rowNum, row)
 {
  var a = row.insertCell(0);
  a.nowrap=true;
  a.setAttribute('align','center');
  if (rowNum<10) displayedRowNum=rowNum+"   ";
  else displayedRowNum=rowNum+" ";
  var displayedRowNum = document.createTextNode(displayedRowNum);
  var textBox1 = document.createElement('input');
  textBox1.setAttribute('type','text');
  textBox1.setAttribute('name','course'+rowNum);
  textBox1.setAttribute('id','course'+rowNum);
  textBox1.setAttribute('size','6');
  a.appendChild(displayedRowNum);
  a.appendChild(textBox1);
  return a;
 }
 function showSecondColumn(rowNum, row)
 {
  var b = row.insertCell(1);
  b.setAttribute('align','center');
  var textBox2 = document.createElement('input');
  textBox2.setAttribute('type','text');
  textBox2.setAttribute('name','credits'+rowNum);
  textBox2.setAttribute('id','credits'+rowNum);
  textBox2.setAttribute('size','3');
  textBox2.onblur=tallyCredits;
  b.appendChild(textBox2);
  return b;
 }
 function showThirdColumn(rowNum, row)
 {
  var c = row.insertCell(2);
  c.setAttribute('align','center');
  var select1 = document.createElement('select');
  select1.setAttribute('name','letterGrade'+rowNum);
  select1.setAttribute('id','letterGrade'+rowNum);
  select1.onchange=tallyCredits;
  var newOption = document.createElement('option');
  newOption.value = '4.0';
  newOption.text = 'A';
  select1.options.add(newOption, 0);
  newOption = document.createElement('option');
  newOption.value = '3.67';
  newOption.text = 'A-';
  select1.options.add(newOption, 1);
  newOption = document.createElement('option');
  newOption.value = '3.33';
  newOption.text = 'B+';
  select1.options.add(newOption, 2);
  newOption = document.createElement('option');
  newOption.value = '3.0';
  newOption.text = 'B';
  select1.options.add(newOption, 3);
  newOption = document.createElement('option');
  newOption.value = '2.67';
  newOption.text = 'B-';
  select1.options.add(newOption, 4);
  newOption = document.createElement('option');
  newOption.value = '2.33';
  newOption.text = 'C+';
  select1.options.add(newOption, 5);
  newOption = document.createElement('option');
  newOption.value = '2.0';
  newOption.text = 'C';
  select1.options.add(newOption, 6);
  newOption = document.createElement('option');
  newOption.value = '1.67';
  newOption.text = 'C-';
  select1.options.add(newOption, 7);
  newOption = document.createElement('option');
  newOption.value = '1.33';
  newOption.text = 'D+';
  select1.options.add(newOption, 8);
  newOption = document.createElement('option');
  newOption.value = '1.0';
  newOption.text = 'D';
  select1.options.add(newOption, 9);
  newOption = document.createElement('option');
  newOption.value = '0.67';
  newOption.text = 'D-';
  select1.options.add(newOption, 10);
  newOption = document.createElement('option');
  newOption.value = '0.0';
  newOption.text = 'F';
  select1.options.add(newOption, 11);
  c.appendChild(select1);
  return c;
 }
 function showFourthColumn(rowNum, row)
 {
  var d = row.insertCell(3);
  d.setAttribute('align','center');
  var textBox3 = document.createElement('input');
  textBox3.setAttribute('type','text');
  textBox3.setAttribute('size','5');
  textBox3.setAttribute('name','qualityPoints'+rowNum);
  textBox3.setAttribute('id','qualityPoints'+rowNum);
  textBox3.readOnly=true;
  d.appendChild(textBox3);
  return d;
 }
 function insertRow()
 {
  var myTable = document.getElementById("GPAOverallTable");
  document.getElementById('deleteRowLink').style.display = 'block';  
  var rowNum = myTable.rows.length-5;<!--number of rows not including header-->
  var newRow = myTable.insertRow(rowNum);
  var x=myTable.tBodies[0].rows.length;
  var a=showFirstColumn(rowNum, newRow);
  var b=showSecondColumn(rowNum, newRow);
  var c=showThirdColumn(rowNum, newRow);
  var d=showFourthColumn(rowNum, newRow);
  var curRows=(x - 1);
 }
 function deleteRow()
 {
  var myTable = document.getElementById("GPAOverallTable");
  var rowNum = myTable.rows.length; <!--number of rows not including header-->
  var courseNum = rowNum-6;
  if (document.getElementById("course"+courseNum).value!="" || document.getElementById("credits"+courseNum).value!="" || document.getElementById("qualityPoints"+courseNum).value!="")
 {
  var confirmation=confirm("You have filled out some fields for course #"+courseNum+".  Are you sure you would like to remove this course?");
 }
 else confirmation=true;
  if (confirmation==true)
  {
     myTable.deleteRow(courseNum);
     if (rowNum==8)document.getElementById('deleteRowLink').style.display = 'none';
  }
  else alert ("Course not deleted.");
  <!--if (rowNum==1) document.gpaForm.deleteRowButton.disabled=true;--> <!--disable 'delete row' button if only header left-->
  tallyCredits();
 }
 function tallyCredits() {
  var totalCredits, totalCreditPoints, GPA, courseNum;
  totalCredits = 0;
  totalCreditPoints = 0;
  var myTable = document.getElementById("GPAOverallTable");
  var numcourses=myTable.tBodies[1].rows.length - 2; //all except for header and footer row
  for (x=1;x<=numcourses;x++)
  {
   if   (document.getElementById("credits"+x).value!="") {
     if  ( (isNaN(document.getElementById("credits"+x).value)) || (eval(document.getElementById("credits"+x).value) > 12)) { 
      window.alert ("Credits for course #"+x+" must be a number from 1-12","NMU GPA")
      document.getElementById("credits"+x).focus()
      return (false);
     } 
     else
     {
      document.getElementById("qualityPoints"+x).value = (document.getElementById("credits"+x).value*document.getElementById("letterGrade"+x).value).toString().substr(0,5);
      totalCreditPoints+=eval(document.getElementById("qualityPoints"+x).value);
      totalCredits += eval(document.getElementById("credits"+x).value);
     } 
   }
  }
  document.gpaForm.totalCredits.value = totalCredits;
  totalCreditPoints = totalCreditPoints.toString();
  document.gpaForm.totalQualPoints.value = totalCreditPoints.substr(0,5);
 
  //calc GPA with totals
  if (document.gpaForm.totalCredits.value!= "" ){
   GPA = eval(document.gpaForm.totalQualPoints.value) / eval(document.gpaForm.totalCredits.value);
   if (isNaN(GPA)) GPA=0;
   document.getElementById("GPA").value = GPA.toPrecision(4);
  }
  calcOverallgpa();
 }
 // compute overall gpa using semester's calculation, and the entered past gpa and credits earned
 function calcOverallgpa() {
  /*if (document.gpaForm.GPA.value == "") {
   window.alert("You need to estimate your current semester GPA first (in the top part of the table).","NMU GPA");
   document.gpaForm.elements[0].focus();
   return (false);
  }*/
  
  //if ( (document.gpaOverallForm.PriorGPA.value == "" ) || 
  if (document.gpaOverallForm.PriorGPA.value != "" && (isNaN(document.gpaOverallForm.PriorGPA.value) || eval(document.gpaOverallForm.PriorGPA.value>4)) ) {
   window.alert ("Prior overall GPA must be entered as a number 4.0 or less","NMU GPA");
   document.gpaOverallForm.PriorGPA.focus();
   return(false);
   }
  
  //if ( (document.gpaForm.PriorCredits.value == "" ) 
  if (document.gpaOverallForm.PriorCredits.value != ""  && (isNaN(document.gpaOverallForm.PriorCredits.value) || eval(document.gpaOverallForm.PriorCredits.value>200)) ) {
   window.alert ("Prior credits taken must be entered as a number 200 or less","NMU GPA");
   document.gpaOverallForm.PriorCredits.focus();
   return(false);
  }
  if (document.gpaOverallForm.PriorGPA.value != "" && document.gpaOverallForm.PriorCredits.value != "")
  {
   var totalCreditPoints, totalCredits, overallGPA;
   if (document.gpaForm.totalCredits.value=="") document.gpaForm.totalCredits.value=0;
   if (document.gpaForm.totalQualPoints.value=="") document.gpaForm.totalQualPoints.value=0;
   totalCredits = eval(document.gpaForm.totalCredits.value) + eval(document.gpaOverallForm.PriorCredits.value);
   totalCreditPoints = eval(document.gpaForm.totalQualPoints.value) + (document.gpaOverallForm.PriorCredits.value * document.gpaOverallForm.PriorGPA.value);
   overallGPA =  totalCreditPoints / totalCredits;
   document.gpaOverallForm.OverallGPA.value = overallGPA.toPrecision(4);
  }
 }
 function clearCourses()
 {
  //must be done for netscape/firefox...won't recognize new dynamically created form fields
  var myTable = document.getElementById("GPAOverallTable");
 var numcourses=myTable.tBodies[1].rows.length - 2; //all except for header and footer row
 for (x=1;x<=numcourses;x++)
 {
  document.getElementById("course"+x).value="";
  document.getElementById("credits"+x).value=""
  document.getElementById("letterGrade"+x).selectedIndex=0;
  document.getElementById("qualityPoints"+x).value="";
 }
 document.gpaForm.reset();
 calcOverallgpa();
 }