function checkIfFilled(value, default_value) 
{ if (value == default_value) 
  { value = '';
  }
  return value;
}
	
function checkIfEmpty(value, default_value) 
{ if (value == '') 
  { value = default_value;
  }
  return value;
}

function setClass(object, classname)
{ object.className = classname;
}

var hoverState = 0;
var lowerClassName = '';

function hoverElement(object)
{ if (hoverState == 0) 
  { lowerClassName = object.className;
    setClass(object, object.className + '_hover');
    hoverState++;
  }
}

function lowerElement(object)
{ if (hoverState == 1)
  { setClass(object, lowerClassName);
    hoverState--;
  }
}