var dtCh= "/";
var minYear=1900;
var maxYear=2100;
var ndates=0;

function isInteger(s){
	var i;
    for (i = 0; i < s.length; i++)
	{   
        // Check that current character is number.
        var c = s.charAt(i);
		
        if (((c < "0") || (c > "9"))) 
		{
		    return false;
		}
    }
    // All characters are numbers.
    return true;
}

function stripCharsInBag(s, bag){
	var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not in bag, append to returnString.
    for (i = 0; i < s.length; i++)
	{   
        var c = s.charAt(i);
		
        if (bag.indexOf(c) == -1) 
		{
		    returnString += c;
		}
    }
	
    return returnString;
}

function daysInFebruary (year){
	// February has 29 days in any year evenly divisible by four,
    // EXCEPT for centurial years which are not also divisible by 400.
    return (((year % 4 == 0) && ( (!(year % 100 == 0)) || (year % 400 == 0))) ? 29 : 28 );
}
function DaysArray(n) {
	for (var i = 1; i <= n; i++) 
	{
		this[i] = 31
		if (i==4 || i==6 || i==9 || i==11)
		{
		    this[i] = 30;
		}
		
		if (i==2) 
		{
		    this[i] = 29;
		}
   }
    
   return this;
}

function isDate(dtStr)
{
	var daysInMonth = DaysArray(12);
	var pos1=dtStr.indexOf(dtCh);
	var pos2=dtStr.indexOf(dtCh,pos1+1);
	
	var strDay=dtStr.substring(0,pos1);
	var strMonth=dtStr.substring(pos1+1,pos2);
	var strYear=dtStr.substring(pos2+1);
	
	strYr=strYear;
	
	if (strDay.charAt(0)=="0" && strDay.length>1)
	{
	    strDay=strDay.substring(1);
	}
	if (strMonth.charAt(0)=="0" && strMonth.length>1) 
	{
	    strMonth=strMonth.substring(1);
	}
	
	for (var i = 1; i <= 3; i++) 
	{
		if (strYr.charAt(0)=="0" && strYr.length>1)
		{
    		strYr=strYr.substring(1);
		}
	}
	
	month=parseInt(strMonth);
	day=parseInt(strDay);
	year=parseInt(strYr);
	
	if (pos1==-1 || pos2==-1)
	{
		alert("The date format should be : dd/mm/yyyy");
		return 1;
	}
	if (strMonth.length<1 || month<1 || month>12)
	{
		alert("Please enter a valid month");
		return 2;
	}
	if (strDay.length<1 || day<1 || day>31 || (month==2 && day>daysInFebruary(year)) || day > daysInMonth[month])
	{
		alert("Please enter a valid day");
		return 1;
	}
	if (strYear.length != 4 || year==0 || year<minYear || year>maxYear)
	{
		alert("Please enter a valid 4 digit year between "+minYear+" and "+maxYear);
		return 3;
	}
	if (dtStr.indexOf(dtCh,pos2+1)!=-1 || isInteger(stripCharsInBag(dtStr, dtCh))==false)
	{
		alert("Please enter a valid date");
		return 1;
	}
	
    return 0;
}

function isblank(s)
{
    for(var i=0;i<s.length;i++)
    {
	    var c = s.charAt(i);
		
		if ((c != ' ') && (c != '\n') && (c != ''))
		{
		    return false;
		}
    }
	
    return true;
}