// @author linda_chuang 

//
// DHTML date validation script. Courtesy of SmartWebby.com (http://www.smartwebby.com/dhtml/)
//
// Declaring valid date character, minimum year and maximum year
var dtCh= "/";
var minYear=1900;
var maxYear=2100;

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



function dateDiff(bYMDStr){
	var a = new Date();  
    a = a.valueOf();    
    a = a - 365 * 24 * 60 * 60 * 1000;
    a = new Date(a);
    dY = a.getFullYear();
    dM = a.getMonth() + 1;
    if(dM < 10){
    	dM = "0" + dM;
    }else{
        dM = "" + dM;
    }//else
    dD = a.getDate();
    if(dD < 10){
        dD = "0" + dD;
    }else{
        dD = "" + dD;
    }//else
    
    var expectDate = dY + "/" + dM + "/" + dD;

    if (bYMDStr < expectDate){     
       alert("Please enter the date within one year."); 
       return false;
    }
    return true;
}


function btnValidate(theForm){ 
// begin date
    var byStr = theForm.begyy.options[theForm.begyy.selectedIndex].value;    
    var bmStr = theForm.begmm.options[theForm.begmm.selectedIndex].value; 
    var bdStr = theForm.begdd.options[theForm.begdd.selectedIndex].value;    
    var bYMDStr = byStr + "/" + bmStr + "/" + bdStr;
    var bStr = bmStr + "/" + bdStr + "/" + byStr;
  

// end date
    var eyStr = theForm.endyy.options[theForm.endyy.selectedIndex].value;
    var emStr = theForm.endmm.options[theForm.endmm.selectedIndex].value;
    var edStr = theForm.enddd.options[theForm.enddd.selectedIndex].value;
    var eYMDStr = eyStr + "/" + emStr + "/" + edStr;
    var eStr = emStr + "/" + edStr + "/" + eyStr;

    

///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////

    if(bYMDStr > eYMDStr){ 
        alert("Please enter a valid date.[Start Date < End Date] "); 
        theForm.begdd.focus();
        return false;
    }

    if(isDate(bStr) == false){ 
        theForm.begdd.focus();
        return false;
    }
 
    if(isDate(eStr) == false){ 
        theForm.enddd.focus();
        return false;
    }   
    
    if (dateDiff(bYMDStr) == false){     
       theForm.begdd.focus();
       return false;    
    }  
    
    return true;
}