// Function to check if the given string is a null string
// or contains any numbers or other characters
// Returns True if only alphabets else returns False
function isAlpha(field){
  var num = parseInt(field.length);
  if (field  == ""){
	return false
  }
  else{
	for (i = 0; i < num; i++){
	  var str = field.substring(i,i+2);
	  if (!((str >= "A" && str <= "Z") || (str >= "a" && str <= "z") || (str==" "))){
		 return false
	  }
	}
  }
  return true
}
// Function to check if the given string is a null string
// or contains any alphabets or other characters
// Returns True if only numbers else returns False
function isNumber(field){
  var num = parseInt(field.length);
  if (field  == ""){
	return false
  }
  else{
	for (i = 0; i < num; i++){
	  var str = field.substring(i,i+2);
	  if (!(str >= "0" && str <= "9")){
		return false
	  }
	}
  }
  return true
}
// Function to Trim the given string of Leading and Trailing spaces
// Returns Trimmed string
function Trim(strInput){
  var i;
  i=0;
  while(i<strInput.length-1){
	if(strInput.charAt(i)==' ')
	  i++;			
	else
	  break;
  }
  strInput= strInput.substr(i);
  i=strInput.length-1;
  while(i>0){
    if(strInput.charAt(i)==' ')
	  i--;			
    else
	  break;
	}
  strInput = strInput.substr(0,i+1);
  return strInput
}
// Function to check if the given string is a null string
// Returns True if Empty else returns False
function isNull(field){
  if(Trim(field) == ""){
	return true
  }
  return false
}
// Function to check if the given string is a valid EMail address or not
// Returns True if valid else returns False
function isEMail(field){
  if(Trim(field) == ''){
	return false;
  }
// First char is @ or . Otherwise No @ or .
  if(field.indexOf("@") <= 0 || field.indexOf(".")<=0){
	return false;
  }
  else{
	var AtLocation;
	AtLocation = field.indexOf("@");
	if(field.indexOf("@",AtLocation+1)>=0){
	  return false;
	}
  }
// No @ or . as the last char
  if(field.indexOf("@") == field.length - 1){
	return false;
  }	           
  if(field.indexOf(".") == field.length - 1){
	return false;
  }	           
// No @ or . as the first char
  if(field.indexOf("@") == 0 || field.indexOf(".") == 0){
	return false;
  }	           
// No characters between @ and .
  if(field.indexOf("@") + 1 == field.lastIndexOf(".")){
	return false;
  }
// Position of @ is before position of .
  if(field.indexOf("@") > field.lastIndexOf(".")){
	return false;
  }
  return true;
}
// Function to check if the given date is a valid date or not
// Returns True if valid else returns False
function isValidDate(field)
{ 
    var dat = Trim(field);
    if  (dat == '') 
	{
	     return false;
	}  
// month validation	
	var sl = dat.indexOf("/");   
    if  (sl != -1){ 
         var m = dat.substring(0,sl); 
         m = Trim(m);
         if (m == "08") m = "8";if (m == "09") m = "9";
         if  (isNumber(m) == false){ 
         return false;
         }
         m = parseInt(m);
         if(m > 12 ||m == 0){
           return false
         }
    }else  return false;
 //Date Validation   
     var sl2 = dat.indexOf("/",sl+1);
     if  (sl2 != -1){
        var d = dat.substring(sl+1,sl2);
        d = Trim(d);
        if(d == "08") d = "8";if(d == "09") d = "9";
        if (isNumber(d) == false){
          return false;
        }
        d = parseInt(d);
        if(d > 31 || d == 0){
           return false;
        }
        if(validDate(d,m) == false){
		   return false;
        }
     }
     else  return false;    
// validation for Year
     var y = dat.substring(sl2+1);
     y = Trim(y);   
     if  (isNumber(y) == false){
       return false;
     }
     y = parseInt(y);
     if ( m == 2 && y % 4 != 0 && d > 28 ){
       return false;
     }
     if( y < 2000 || y > 9999){ 
       return false;
     }
    else return true;  
}
function validDate(dd,mm)
{
if ( mm == 1 && dd <=31 ) return true; if ( mm == 2 && dd <=29 ) return true;
if ( mm == 3 && dd <=31 ) return true; if ( mm == 4 && dd <=30 ) return true;
if ( mm == 5 && dd <=31 ) return true; if ( mm == 6 && dd <=30 ) return true;
if ( mm == 7 && dd <=31 ) return true; if ( mm == 8 && dd <=31 ) return true;
if ( mm == 9 && dd <=30 ) return true; if ( mm == 10 && dd <=31 ) return true;
if ( mm == 11 && dd <=30 ) return true; if ( mm == 12 && dd <=31 ) return true;
return false;
}