bSubmit = 0;

function navig( url ) 
{	
	if( bSubmit == 1 ) 
	{
//		alert( "Запрос уже послан." );
//		return false;	//avoid multiple submit
	}
//	bSubmit = 1; 
	document.forms[0].action = url; 
	document.forms[0].submit(); 
	return false;
}

function trimWhiteSpace( buf ) 
{
	// remove leading spaces
	var len = buf.length;
	while( len > 0 ) {
		var s = buf.charAt( 0 );
		if( s == " " || s == "\n" || s == "\r" ) {
			len --;
			buf = buf.substr( 1, len );
		} 
		else break;
	}

	// remove trailing spaces
	while( len > 0 ) {
		var s = buf.charAt( len - 1 );
		if( s == " " || s == "\n" || s == "\r" ) {
			len --;
			buf = buf.substr( 0, len );
		} 
		else break;
	}
	return buf;
}

function openit( url, w, h, scroll, resize, left, top, nwi )
{
	if( url == "" ) return;
	
	var thisloc = "" + window.location;
	if( "" + w == "undefined" ) w = 780;
	if( "" + h == "undefined" ) h = 570;
	if( "" + scroll == "undefined" ) scroll = 'yes';
	if( "" + resize == "undefined" ) resize = 'yes';
	if( "" + left == "undefined" ) {
		left = ( screen.width - w ) / 2;
		if( left < 0 ) {
			left = 0;
			w = screen.width;
		}
	}
	if( "" + top == "undefined" ) {
		top = ( screen.height - h - 30 ) / 2;
		if( top < 0 ) {
			top = 0;
			h = screen.height - 30;
		}
	}
	if( "" + nwi == "undefined" ) nwi = '_blank';

	var pos2 = url.toLowerCase().indexOf("http:"), loc = "";
	if( pos2 < 0 && url.charAt( 0 ) != "/" )
	{	//relative path
		var pos = thisloc.lastIndexOf("/");
		if( pos >= 0 )
		{
			loc = thisloc.substring(0, pos+1) + url;
		}
	}
	else loc = url;
	
	if( loc == "" ) 
	{
		alert( "Empty url!" );
		return;
	}

	window.open( loc, nwi, 'width=' + w + ',height=' + h + ',left=' + left + ',top=' + top + ',scrollbars=' + scroll + ',resizable=' + resize );
	return;
}

//sDate like 'dd.mm.yyyy'
function checkDate( sDate, yMin, yMax )
{
	var dd, mm, yy;
	if( "" + yMin == "undefined" ) yMin = 1902;
	if( "" + yMax == "undefined" ) yMax = 2031;
	var arr = sDate.split( "." );
	if( arr.length != 3 )
	{	//try MM/DD/YYYY
		arr = sDate.split( "/" );
		if( arr.length != 3 ) return "";
		dd = new Number( arr[ 1 ] );
		mm = new Number( arr[ 0 ] );
		yy = new Number( arr[ 2 ] );
	}
	else
	{
		dd = new Number( arr[ 0 ] );
		mm = new Number( arr[ 1 ] );
		yy = new Number( arr[ 2 ] );
	}
	if( isNaN( dd ) || dd <= 0 || dd > 31 ) return "";
	if( isNaN( mm ) || mm <= 0 || mm > 12 ) return "";
	if( isNaN( yy ) || yy < yMin || yy > yMax ) return "";
	
	return sDate;
}

//cookie support
function findCookie(szName)
{
	var nameEQ = szName + "=";
	var ca = document.cookie.split(';');
	for( var i=0; i < ca.length; i++ )
	{
		var c = ca[i];
		while( c.charAt(0) == ' ' ) c = c.substring( 1, c.length );
		if( c.indexOf(nameEQ) == 0 ) return c.substring( nameEQ.length, c.length );
	}
	return null;
}
function addCookie(szName,szVal,dtDays)
{
	var dtExp = new Date();
    var dtEDate = "";
	dtExp.setTime( dtExp.getTime() + dtDays*24*60*60*1000 );
	dtEDate = dtExp.toGMTString();
	document.cookie = szName + "=" + szVal + "; expires=" + dtEDate + "; path=/";
	return;
}
function delCookie(szName)
{
    addCookie(szName,"",-1);
}

//launch help-course
function helpme( id )
{
	var w, h, left = 10, top = 10;
	w = screen.width - 20;
	if( w > 800 ) w = 800;
	h = screen.height - 60;
	if( h > 600 ) h = 600;
	openit( "/courses/course75/index.htm?pid=" + id, w, h, 'yes', 'yes', left, top );
	return false;
}

//image functions
function newImage(arg)
{
	if (document.images)
	{
		var rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}
function changeImages()
{
	if (document.images)
	{
		for (var i=0; i<changeImages.arguments.length; i+=2)
		{
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}