function calculateHeight()
{
    var contentHeight = 0;

    // get the height of the 3 columns and set contentheight to the largest value
    if (document.getElementById('banners')) {
        contentHeight = document.getElementById('banners').offsetHeight;
    }

    if (document.getElementById('content')) {
        if (document.getElementById('content').offsetHeight > contentHeight) {
            contentHeight = document.getElementById('content').offsetHeight;
        }
    }

    if (document.getElementById('content_right')) {
        if (document.getElementById('content_right').offsetHeight > contentHeight) {
            contentHeight = document.getElementById('content_right').offsetHeight;
        }
    }

    contentHeight += 35;

    // put the opacity div heights
    document.getElementById('content_left_background').style.height = contentHeight + "px";
    document.getElementById('content_left_wrapper').style.height = contentHeight + "px";
    document.getElementById('content_left').style.height = contentHeight + "px";

    document.getElementById('content_right_background').style.height = contentHeight + "px";
    document.getElementById('content_right_wrapper').style.height = contentHeight + "px";
    document.getElementById('content_right').style.height = contentHeight + "px";
}

function open_menu(menu, clickedItem)
{
    menu.style.display = 'block';
    clickedItem.style.background = '#0054A4';

}

function close_menu(menu, clickedItem)
{
    menu.style.display = 'none';
    clickedItem.style.background = '#A0CBED';
}

function FocusCol(obj)
{
	if (document.getElementById ||
		document.all)
	{
		obj.style.color="#000000";
		obj.style.backgroundColor="#FFFFFF";
		obj.style.fontWeight="normal";
		}
	}
	
function BlurCol(obj)
{
	if (document.getElementById ||
		document.all)
	{
		obj.style.color="#666666";
		obj.style.backgroundColor="#EFEDE7";
		obj.style.fontWeight="normal";
		}
}

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_validateForm() { //v4.0
  var i,p,q,nm,test,num,min,max,errors='',args=MM_validateForm.arguments;
  for (i=0; i<(args.length-2); i+=3) { test=args[i+2]; val=MM_findObj(args[i]);
    if (val) { nm=val.name; if ((val=val.value)!="") {
      if (test.indexOf('isEmail')!=-1) { p=val.indexOf('@');
        if (p<1 || p==(val.length-1)) errors+='- '+nm+' dient een gelding emailadres te zijn.\n';
      } else if (test!='R') { num = parseFloat(val);
        if (isNaN(val)) errors+='- '+nm+' dient een nummer te zijn.\n';
        if (test.indexOf('inRange') != -1) { p=test.indexOf(':');
          min=test.substring(8,p); max=test.substring(p+1);
          if (num<min || max<num) errors+='- '+nm+' must contain a number between '+min+' and '+max+'.\n';
    } } } else if (test.charAt(0) == 'R') errors += '- '+nm+' is een verplicht veld.\n'; }
  } if (errors) alert('De volgende fouten hebben zich voorgedaan:\n'+errors);
  document.MM_returnValue = (errors == '');
}