function checkThis(rij, vink)
{
  document.getElementById(rij + "v1").className = "";
  document.getElementById(rij + "v2").className = "";
  document.getElementById(rij + "v3").className = "";
  document.getElementById(rij + "v4").className = "";
  document.getElementById(rij + vink).className = "vchecked";
  
  var date = new Date();
  frames["extraframe"].location.href = "/actions/watweetikal.aspx?rij=" + rij + "&vink=" + vink + "&" + date.getTime();
}