//list of required fields
list = new Array (1,2,4,8,10);

//fields checker
function checker(field_number)
	{
empty_field=NaN;
form_element=document.forms['download_form'].elements[field_number];
if (form_element.type=='text') if (!form_element.value) empty_field=field_number;
if (form_element.type=='select-one') if (!form_element.options.selectedIndex) empty_field=field_number
return empty_field;
	};
	
//form checker
function gonext()
	{
field_number=-1;
for (i=list.length-1; i>=0; i--)
		{
	if (!isNaN(checker(list[i]))) field_number=list[i]
		};

if (field_number!=-1)
		{
	field=document.forms['download_form'].elements[field_number];
	alert('Не вся поля формы правильно заполнены. Проверьте выделенное поле.');
	field.focus();
	if (field.type!='select-one') field.select();
		}
else
		{
	document.forms['download_form'].action="scripts/download_r.php";
	document.forms['download_form'].submit()
		}
	}
//-->