function validateSize(id, size){
  var element = document.getElementById(id);
  if (element.value.length > size){
   alert("Feltet er maks "+size+" tegn!");
   return false;
  }else {
    return true;
  }
}

function validateEmpty(id, tekst){
  var element = document.getElementById(id);
  if (element.value.length == 0){
   alert(tekst+" må angis!");
   return false;
  }else {
    return true;
  }
}

function textCounter(field, id, maxlimit) {
  var c = document.getElementById(id);
  var f = document.getElementById(field);
  c.value = maxlimit - f.value.length;
}

function validateURL(id){
  var element = document.getElementById(id);
  var str = element.value;
  if (element.value.substr(0, 7) == "http://"){
    alert("URL skal ikke starte med 'http://'!");
    element.value = element.value.substr(7, element.value.length);
  }
}

function toggleDisplay(id){
  var element = document.getElementById(id);
  if (element.style.display == "none"){
    element.style.display = '';//type, IE skjønner ikke display: table-row og lignende...;
  }else {
    element.style.display = "none";
  }
}

function displayPlakatValg(action){
  var element1 = document.getElementById("plakat1");
  var element2 = document.getElementById("plakat2");
  var element3 = document.getElementById("plakat3");
  var element4 = document.getElementById("plakat4");
  var element5 = document.getElementById("plakat5");
  var element6 = document.getElementById("plakat6");
  if (action == "vis"){
    element1.style.display = '';
    element2.style.display = '';
    element3.style.display = '';
    element4.style.display = '';
    element5.style.display = '';
    element6.style.display = '';
  }else {
    element1.style.display = "none";
    element2.style.display = "none";
    element3.style.display = "none";
    element4.style.display = "none";
    element5.style.display = "none";
    element6.style.display = "none";
  }
}

function toggleBackground(id, type){
  var element = document.getElementById(id);
  if (type == "medium"){
    element.style.background = "#CCCBBA";
  }else if (type == "lys"){
    element.style.background = "#DDDCCB";
  }else if (type == "mørk"){
    element.style.background = "#BBBAA0";
  }
}