function setValue(setto, myElement)
{	
  var boxElement = document.getElementById(myElement);
  boxElement.value = setto;
}

function getValue(myElement)
{	
  var boxElement = document.getElementById(myElement);
  return boxElement.value;
}


function minusOne(fieldName)
{
  var thisElem = document.getElementById(fieldName);
  if (thisElem.value > 1) {
    thisElem.value--;
  }
}

function plusOne(fieldName, maxPage)
{
  var thisElem = document.getElementById(fieldName);
  if (thisElem.value < maxPage) {
    thisElem.value++;
  }
}

function addValue(N, fieldName, maxPage)
{
  var thisElem = document.getElementById(fieldName);
  if (thisElem.value < maxPage) {
    thisElem.value += N;
  }
}