function initzoekterm() {
  var label = document.getElementById("zoeklabel");
  var field = document.getElementById("zoekterm");
  
  label.style.display = "block";
  
  if (field.value !== '') {
    hideLabel(label, true);
  }

  // Set handlers to show and hide labels.
  field.onfocus = function () {
    hideLabel(label, true);
  };
  field.onblur = function () {
    if (this.value === '') {
      hideLabel(label, false);
    }
  };
  label.onclick = function() {
    hideLabel(label, true);
    field.focus();
  }
}

function hideLabel(label, hide) {
  label.style.textIndent = (hide) ? '-2000px' : '0px';
}

onload = initzoekterm;