// mutagenesis.js

var page; //this will determine the answer, previous, and
var correct;

/*******************************************************************
  Function: Initialize
  This is called with the onload command.
  ####The onload must supply the page number####
*******************************************************************/
function Initialize(number)
{
  page = number;
  switch (page) //determine which pages have questions
  {
    case 1:
    case 2:
    case 3:
    case 4:
      correct = false; //these pages have questions
      DisplayMessage(0);
      break;
    default:  //these pages don't have questions
      correct = true;
      DisplayMessage(1);
      break;
  } //end switch
} //end Initialize

/*******************************************************************
  Function: GoToOutline
*******************************************************************/
function GoToOutline()
{
  window.location="index.html";
} //end GoToOutline

/*******************************************************************
  Function GoBack
*******************************************************************/
function GoBack()
{
  switch(page)
  {
    case 1:
      page_name = "index.html";
      break;
    case 2:
      page_name = "mutagenesis01.html";
      break;
    case 3:
      page_name = "mutagenesis02.html";
      break;
    case 4:
      page_name = "mutagenesis03.html";
      break;
    case 5:
      page_name = "mutagenesis04.html";
      break;
    default:
      page_name = "index.html";
      break;
  } //end switch
  window.location=page_name; //go to the page
} //end GoBack

/*******************************************************************
  function GoToNext
*******************************************************************/
function GoToNext()
{
  if (correct==true)
  {
    switch(page)
    {
      case 1:
        page_name = "mutagenesis02.html";
        break;
      case 2:
        page_name = "mutagenesis03.html";
        break;
      case 3:
        page_name = "mutagenesis04.html";
        break;
      case 4:
        page_name = "mutagenesis05.html";
        break;
      case 5:
        page_name = "index.html";
        break;
      default:
        page_name = "index.html";
        break;
    } //end switch
  window.location=page_name; //go to the page
  } //end if
  else
  {
    DisplayMessage(4);
  } //end else
} //end GoToNext

/*******************************************************************
  function CheckAnswer
  this function calls the appropriate function to check the answer.
*******************************************************************/
function CheckAnswer()
{
  switch (page)
  {
    case 1:
      Answer1();
      break;
    case 2:
      Answer2();
      break;
    case 3:
      Answer3();
      break;
    case 4:
      Answer4();
      break;
    case 5:
      Answer5();
      break;
    default:
      break;
  } //end switch
} //end CheckAnswer

/*******************************************************************
  function Answer1
  this function determines the answer for page1 of mutagenesis
*******************************************************************/
function Answer1()
{
  switch(GetRadioValue())
  {
   case "button1":
   case "button2":
   case "button4":
     DisplayMessage(2);
     correct = false;
     break;
   case "button3":
     DisplayMessage(3);
     correct = true;
     break;
   default:	
     DisplayMessage(4);
     correct = false;
     break;
  } //end switch
} //end Answer1

/*******************************************************************
  function Answer2
*******************************************************************/
function Answer2()
{
  switch(GetRadioValue())
  {
   case "button1":
   case "button2":
   case "button3":
   case "button5":
   case "button6":
   case "button7":
   case "button8":
     DisplayMessage(2);
     correct = false;
     break;
   case "button4":
     DisplayMessage(3);
     correct = true;
     break;
   default:	
     DisplayMessage(4);
     correct = false;
     break;
  } //end switch
} //end Answer2

/*******************************************************************
  function Answer3
*******************************************************************/
function Answer3()
{
  if ((document.form.textarea1.value=="")||(document.form.textarea2.value=="")||(document.form.textarea3.value==""))
  {
     DisplayMessage(4);
     correct = false;
  } //end if
  else
  {
     DisplayMessage(1);
     correct = true;
  } //end else
} //end Answer3

/*******************************************************************
  function Answer4
*******************************************************************/
function Answer4()
{
  if (document.form.textarea1.value=="")
  {
     DisplayMessage(4);
     correct = false;
  } //end if
  else
  {
     DisplayMessage(1);
     correct = true;
  } //end else
} //end Answer4

/*******************************************************************
  function Answer5
*******************************************************************/
function Answer5()
{
 DisplayMessage(5);
 correct = true;
} //end Answer5


/*******************************************************************
  function GetRadioValue
  returns the name of the button which is active
*******************************************************************/
 function GetRadioValue()
 {
  var input = document.form.radiobutton
  var value = null
  for (var i=0; i<input.length; i++) {
   if(input[i].checked) {
    value = input[i].value
    break
   }
  }
  return value
 } //end GetRadioValue


/*******************************************************************
  function DisplayMessage
  parameter: 0,1,2,3,4
*******************************************************************/
function DisplayMessage(msg_type)
{
  switch (msg_type)
  {
    case 0:
      document.form.message_field.value="Please click on Check Answer before continuing."
      break;
    case 1:
      document.form.message_field.value="Please click on Next to continue."
      break;
    case 2:
      document.form.message_field.value="Incorrect answer. Please try again."
      break;
    case 3:
      document.form.message_field.value="Correct answer. Click on Next to continue."
      break;
    case 4:
      document.form.message_field.value="You must answer the question and click on Check Answer to continue."
      break;
    case 5:
      document.form.message_field.value="There are no questions for this section. Click Next to continue."
      break;
    default:
      document.form.message_field.value="Please click on Check Answer before continuing."
      break;
  } //end switch
} //end DisplayMessage