function _search( categoria ) {
	var s = document.getElementById('search_container');
	var c = document.getElementById('search_category');
	var t = document.getElementById('searcht');
	var sb = document.getElementById('searchf');
	if ( s )
	{
		if ( categoria == 'subject' )
		{
			t.style.display = 'block';
			sb.style.display = 'none';
			sb = t;
		}
		else
		{
			t.style.display = 'none';
			t.selectedIndex = 0;
			sb.style.display = 'block';
		}
		s.style.display = 'block';
		c.value = categoria;
		sb.focus();
	}
	var l1 = document.getElementById('searchbytitle');
	var l2 = document.getElementById('searchbyauthor');
// 	var l3 = document.getElementById('searchbykeywords');
	var l4 = document.getElementById('searchbysubject');
// 	var l5 = document.getElementById('searchbydate');
	var l6 = document.getElementById('searchby'+categoria);
	l1.style.fontWeight = l2.style.fontWeight = l4.style.fontWeight = 'normal';
	l6.style.fontWeight = 'bold';
}