function showImg(img, id, pos) {

  if (pos == 'h') {

    var wi = 533;

    var he = 400;

  }

  else {

    var wi = 400;

    var he = 533;

  }

  var x = cmGetX (document.getElementById('main_table')) + (400 / 2) - (wi / 2);
  var y = cmGetY (document.getElementById('main_table')) + (554 / 2) - (he / 2) - 10;

  document.getElementById('picviewer').style.top = y;
  document.getElementById('picviewer').style.left = x;

  document.getElementById('picviewer').innerHTML = '<img style="cursor:pointer;" alt="Click to close" src="'+id+'" id="picsrc" border=0 onclick="hideImg()"></center>';

  document.getElementById('picviewer').style.display = 'block';

  showSelect('hidden');

}

function hideImg() {

  document.getElementById('picviewer').style.display = 'none';
 
  showSelect('visible');

}

function showSelect(status) {

  var tagName = 'select';

  var subMenu = document.getElementById('picviewer');

  var x = cmGetX (subMenu);
  var y = cmGetY (subMenu);
  var w = subMenu.offsetWidth;
  var h = subMenu.offsetHeight;

  var i;

  for (i = 0; i < document.all.tags(tagName).length; ++i) {

    var obj = document.all.tags(tagName)[i];
 
    if (!obj || !obj.offsetParent) continue;

    if (obj.name == 'sItem') continue;

    var ox = cmGetX (obj);
    var oy = cmGetY (obj);
    var ow = obj.offsetWidth;
    var oh = obj.offsetHeight;

    if (ox > (x + w) || (ox + ow) < x) continue;

    if (oy > (y + h) || (oy + oh) < y) continue;

    obj.style.visibility = status;

  }

}


function cmGetX (obj)
{
	var x = 0;

	do
	{
		x += obj.offsetLeft;
		obj = obj.offsetParent;
	}
	while (obj);
	return x;
}

function cmGetXAt (obj, elm)
{
	var x = 0;

	while (obj && obj != elm)
	{
		x += obj.offsetLeft;
		obj = obj.offsetParent;
	}
	return x;
}

function cmGetY (obj)
{
	var y = 0;
	do
	{
		y += obj.offsetTop;
		obj = obj.offsetParent;
	}
	while (obj);
	return y;
}

function cmGetYAt (obj, elm)
{
	var y = 0;

	while (obj && obj != elm)
	{
		y += obj.offsetTop;
		obj = obj.offsetParent;
	}
	return y;
}

function showPic(id) {

	if (id > 0) {

		document.getElementById('preview_image').style.backgroundImage = 'url(/image.php?size=160&id='+id+')';

	}

	else {

		document.getElementById('preview_image').style.backgroundImage = '';

	}

}


function checkForm(form) {

  var aantal = form.elements.length;

  var string = 'U heeft de volgende verplichte veld(en) niet ingevuld: \n';

  string += '-------------------------------------------------------\n';

  var returnbool = true;

  for (var i=0;i<aantal;i++) {

    if (form.elements[i].type == 'checkbox') {

      if (form.elements[i].title.length > 0 && !form.elements[i].checked) {

	string += form.elements[i].title+'\n';

        returnbool = false;

      }

    }

    else if (form.elements[i].value.length == 0 && form.elements[i].title.length > 0 && !form.elements[i].disabled && form.elements[i].style.display != 'none') {

      string += form.elements[i].title+'\n';

      returnbool = false;

    }

  }

  if (returnbool) {

    return true;

  }

  else {

  	string += '-------------------------------------------------------\n';

    string += 'Vul deze velden in om de actie te voltooien';

    alert(string);

    return false;

  }

}