function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}


function Rows()
{
  var tableOfContents = document.getElementById("puzzle");
  var rows   = tableOfContents.getElementsByTagName("tr");
  return (rows.length);
}

function Reset()
{
  var trows  = Rows();
  var tminus = trows - 1;

  for (var line=0;line<tminus;line++)
  {
    for (var column=0;column<tminus;column++)
    {
      var offset = (line * trows) + column;
      document.sudtable.elements[offset].style.backgroundColor = "#FFFFFF";
    }
  }
}

function ErrCol(xy1, xy2)
{
  document.sudtable.elements[xy1].style.background = "#FF0000";
  document.sudtable.elements[xy2].style.background = "#FF0000";
}

function Check()
{   

  Reset();

  var trows  = Rows();
  var tminus = trows - 1;

  var ablank = 0;

  for (var line=0;line<trows;line++)
  {
    for (var column=0;column<trows;column++)
    {
      var offset = (line * trows) + column;
      var comp   = document.sudtable.elements[offset].value;

      if (comp == "") 
      {
        ablank = 1;
      }

      if (comp != '' && (comp > trows || comp < 1))
      {
         ErrCol(offset,offset);

         alert('Sudoku Failed\n\nLine: ' + (line+1) + ' Column ' + (column+1) + '. Number must be between 1 and ' + trows);
         return false;
      }

      if (column<tminus)
      {
        for (var pointer=column+1;pointer<trows;pointer++)
        {
          var offset2 = (line * trows) + pointer;

	  var comp2   = document.sudtable.elements[offset2].value;

          if (comp == comp2 && comp != "")
          {
            ErrCol(offset,offset2);

            alert('Sudoku Failed\n\nLine: ' + (line+1) + ' Column ' + (column+1) + ' matches column ' + (pointer+1) );

            return false;

          }
        } // Move along the line from the exam point
      } // No need comparing the last in the column

      if (line<tminus)
      {
        for (var pointer2=line+1;pointer2<trows;pointer2++)
        {
          offset2 = (pointer2 * trows) + column;
          comp2   = document.sudtable.elements[offset2].value;

          if (comp == comp2 && comp != "")
          {
            ErrCol(offset,offset2);

            alert('Column: ' + (column+1) + ' Line ' + (line+1) + ' matches line ' + (pointer2+1));

            return false;
          }
        }
      } // No need to compare the last line in the table
    } // Move the exam point along the line
  } // Move down

  if (ablank == 0)
  {
    alert ('SUCCESS !! \n Sudoku Completed. \n Well Done.');
  }
  else
  {
    alert ('Sudoku is OK so far..');
  }
  
  return false;
} 


var	timerID = null
var	timerRunning = false
var	startDate
var	elapsedSecs = 0

function stopclock()
{
	if(timerRunning)
		clearTimeout(timerID)
		timerRunning = false
}

function startclock()
{
	stopclock()
	showtime()
}

function blankgrid(zap)
{
  var trows  = Rows();
  var tminus = trows - 1;

  for (var line=0;line<=tminus;line++)
  {
    for (var column=0;column<=tminus;column++)
    {
      var offset = (line * trows) + column;

      {
        if (zap)
        {
          document.sudtable.elements[offset].style.backgroundColor = "#0000E0";
        }
        else 
        {
          document.sudtable.elements[offset].style.backgroundColor = "#FFFFFF";
        }
      }
    }
  }
}

function toggleclock()
{
  if(timerRunning)
  {
    stopclock()
    blankgrid(true)
    document.timerForm.B3.value = "start"
    
  }
  else
  {
    blankgrid(false)
    showtime()
    document.timerForm.B3.value = "pause"
  }
}

function showtime()
{
	// this doesn't work correctly at midnight...

	elapsedSecs = elapsedSecs + 1;

	var hours = Math.floor( elapsedSecs / 3600 )
//elapsedSecs = elapsedSecs - (hours*3600)

	var minutes = 	Math.floor( elapsedSecs / 60 )
//elapsedSecs = elapsedSecs - (minutes*60)

	var seconds = elapsedSecs % 60

	var timeValue = "" + hours
	timeValue  += ((minutes < 10) ? ":0" : ":") + minutes
	timeValue  += ((seconds < 10) ? ":0" : ":") + seconds

		// Update display
	document.timerForm.timerField.value = timeValue 
	timerID = setTimeout("showtime()",1000)
	timerRunning = true
}