var submitted = false;

function show_help(){
	document.getElementById('hlp').style.display = "inline";
	document.getElementById('ahlp').style.display = "none";
	return false;
}
function hide_help(){
	document.getElementById('hlp').style.display = "none";
	document.getElementById('ahlp').style.display = "inline";
	return false;
}
function isdefined( variable)
{
    return (typeof(variable) == "undefined")?  false: true;
}

function check_history_form()
{
	var error = 0;
	var i;
 
	var error_message = "";
	if(submitted) { alert( "Tento formulár už bol odoslaný."); return false; }

	var hist   	= document.getElementById('historia').value;

	if ( hist.length == '' || hist.length < 3 || hist.indexOf("_")>0 || hist.indexOf("%")>0 )
	{
		error_message = error_message + "Zadajte minimálne 3 znaky, nepoužívajte špeciálne znaky.\n";
		error = 1;
	} 

	if (error == 1) { alert(error_message); return false; } else { submitted = true; return true; }
}