// lijst van boeken op search pagina
function ShowBooks(list)
{
	var idAuthor = (list.options[list.selectedIndex].value)
	location = '/search/searchtxt.php?AuthorID='+idAuthor
}

function ShowTitle(list)
{
	var idTitle = (list.options[list.selectedIndex].value)
	location = '/book/book2.php?Book='+idTitle
}

// check newsletter

function checkform() {
  for (i=0;i<fieldstocheck.length;i++) {
    if (eval("document.subscribeform.elements['"+fieldstocheck[i]+"'].type") == "checkbox") {
      if (document.subscribeform.elements[fieldstocheck[i]].checked) {
      } else {
        alert("Please enter your "+fieldnames[i]);
        eval("document.subscribeform.elements['"+fieldstocheck[i]+"'].focus()");
        return false;
      }
    }
    else {
      if (eval("document.subscribeform.elements['"+fieldstocheck[i]+"'].value") == "") {
        alert("Please enter your "+fieldnames[i]);
        eval("document.subscribeform.elements['"+fieldstocheck[i]+"'].focus()");
        return false;
      }
    }
  }
  for (i=0;i<groupstocheck.length;i++) {
    if (!checkGroup(groupstocheck[i],groupnames[i])) {
      return false;
    }
  }
  
  return true;
}

var fieldstocheck = new Array();
var fieldnames = new Array();
function addFieldToCheck(value,name) {
  fieldstocheck[fieldstocheck.length] = value;
  fieldnames[fieldnames.length] = name;
}
var groupstocheck = new Array();
var groupnames = new Array();
function addGroupToCheck(value,name) {
  groupstocheck[groupstocheck.length] = value;
  groupnames[groupnames.length] = name;
}

function compareEmail()
{
  return (document.subscribeform.elements["email"].value == document.subscribeform.elements["emailconfirm"].value);
}
function checkGroup(name,value) {
  option = -1;
  for (i=0;i<document.subscribeform.elements[name].length;i++) {
    if (document.subscribeform.elements[name][i].checked) {
      option = i;
    }
  }
  if (option == -1) {
    alert ("Please enter your "+value);
    return false;
  }
  return true;
}


// cookies //

function getCookie (name) {
    var prefix = name + '=';
    var c = document.cookie;
    var nullstring = '';
    var cookieStartIndex = c.indexOf(prefix);
    if (cookieStartIndex == -1)
        return nullstring;
    var cookieEndIndex = c.indexOf(";", cookieStartIndex + prefix.length);
    if (cookieEndIndex == -1)
        cookieEndIndex = c.length;
    return unescape(c.substring(cookieStartIndex + prefix.length, cookieEndIndex));
}

// nav select //

function nav(sel) {
   if (sel.selectedIndex == -1) return;
   var opt = sel.options[sel.selectedIndex];
   if (opt && opt.value)
      location.href = opt.value;
}