function pushArray(array1, newValue)
{
  array1.push(newValue.value);
  newValue.value = "";
  showArray(array1);
  lengthArray(array1);
}
  
function popArray(array1, displayField)
{
  displayField.value = "";
  var popped = array1.pop();
  displayField.value = popped;
  showArray(array1);
  lengthArray(array1);
}
    
function unshiftArray(array1, newValue)
{
  array1.unshift(newValue.value);
  newValue.value = "";
  showArray(array1);
  lengthArray(array1);
}
  
function shiftArray(array1, displayField)
{
  displayField.value = "";
  var shifted = array1.shift();
  displayField.value = shifted;
  showArray(array1);
  lengthArray(array1);
}