// JavaScript Document
<!--

function showchart(){
	var dt = document.form1.myselector;
	var mylinker = "http://climate.sdstate.edu/w_info/et/charts/" + dt.value + ".png";	
	if (dt.value == '---'){}else{		
		window.location.href = mylinker;
		return true;
	}
}

function loaddates()
{
	var date = new Date();
	var oneday = 1000*60*60*24;;
	var yesterday = new Date(date.getTime() - oneday); 
	document.gddform.txtfrom.value = (yesterday.getMonth()+1) + "/" + yesterday.getDate() + "/" + yesterday.getFullYear(); 
	document.gddform.txtto.value = (yesterday.getMonth()+1) + "/" + yesterday.getDate() + "/" + yesterday.getFullYear();
}

function changestation(whatnum,whatchartnum)
{
	for (var i=0; i<document.gddform.stationz.length;++i)
	{
		if (document.gddform.stationz.options[i].value == whatnum)
		{
			document.gddform.stationz.options[i].selected = true;
		}
	}	
	for (i=0; i<document.form1.myselector.length;++i)
	{
		if (document.form1.myselector.options[i].value == whatchartnum)
		{
			document.form1.myselector.options[i].selected = true;	
		}
	}
}


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 IsNumeric(sText)
{
   var ValidChars = "0123456789";
   var IsNumber=true;
   var Char;

   for (i = 0; i < sText.length && IsNumber == true; i++) 
      { 
      Char = sText.charAt(i); 
      if (ValidChars.indexOf(Char) == -1) 
         {
         IsNumber = false;
         }
      }
   return IsNumber;
   
   }

function ValidateForm(){
	var dt=document.gddform.txtfrom
	if (isDate(dt.value)==false){
		alert("Enter a valid date in the FROM field")
		dt.focus()
		dt.select()
		return false
	}
	dt=document.gddform.txtto
	if (isDate(dt.value)==false){
		alert("Enter a valid date in the TO field")	
		dt.focus()
		dt.select()
		return false
	}	

	dt=document.gddform.choicez
	if (dt.value==""){
		alert("Please choose atleast one field for display")
		dt.focus()
		return false
	}
	
	var firstdate = new Date(document.gddform.txtfrom.value)
	var seconddate = new Date(document.gddform.txtto.value)
	if (firstdate > seconddate)
	{
		alert("Starting date is greater than ending date. Please re-enter dates");
		document.gddform.txtfrom.focus();
		return false;
	}
		
    return true
 }

-->