// JavaScript Document

/////////////////////////////////////numeric check///////////////////////////////////

function IsNumeric(strString)
   //  check for valid numeric strings	
   {
   var strValidChars = "0123456789.-";
   var strChar;
   var blnResult = true;

   if (strString.length == 0) return false;

   //  test strString consists of valid characters listed above
   for (i = 0; i < strString.length && blnResult == true; i++)
      {
      strChar = strString.charAt(i);
      if (strValidChars.indexOf(strChar) == -1)
         {
         blnResult = false;
         }
      }
   return blnResult;
   }
///////////////////////////validate() procedure////////////////////////
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 validate()
{

var txt_name = document.getElementById("txt_name"),
    txt_des = document.getElementById("txt_des"),
	txt_add = document.getElementById("txt_add"),
	txt_city = document.getElementById("txt_city"),
	txt_state = document.getElementById("txt_state"),
	txt_zip = document.getElementById("txt_zip"),
	txt_email = document.getElementById("txt_email");
	
	////first name/////
	if(txt_name.value ==""){
		alert("Please specify your name!")
		txt_name.focus();
		return false;
	}
		////address/////
	if(txt_add.value ==""){
		alert("Please specify your address!")
		txt_add.focus();
		return false;
	}

	////city/////
	if(txt_city.value ==""){
		alert("Please specify your city!")
		txt_city.focus();
		return false;
	}

	////state/////
	if(txt_state.value ==""){
		alert("Please specify your state!")
		txt_state.focus();
		return false;
	}
	
	///zip code////
	if(txt_zip.value == ""){
		alert("Please specify your zip code!")
		txt_zip.focus();
		return false;
	}
	
	////email////
	if(txt_email.value==""){
		alert("Please specify your email address!")
		txt_email.focus();
		return false;
	}
	var at=txt_email.value.indexOf("@");
	var dot=txt_email.value.lastIndexOf(".");	
	if(dot<=at){
		alert("Your email address does not seems to be valid!")
		txt_email.focus();
		return false;
	}

	///comments////	
	if(txt_des.value ==""){
		alert("Please specify your comments!")
		txt_des.focus();
		return false;
	}

return true	
}

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