function getExtraInfo()
{

	var element_o = document.getElementById('extra_content');
		element_o.style.display = '';

		 element_o = document.getElementById('extra_button');
		element_o.style.display = 'none';
};

function setDisplaySwitch(element_s)
{
	var element_o = document.getElementById(element_s);
		element_o.className =(element_o.className == 'hidden') ? '' : 'hidden';

};


function setExtra(select_o, value_s, field_s)
{
	var value_u = select_o.options[select_o.selectedIndex].value;

	if (value_u == value_s)
	{

		element_o = document.getElementById(field_s);      
		element_o.className =(element_o.className == 'hidden') ? '' : 'hidden';
	}
}