//****************************************************
// Funciones de manejo string y validaciones
// 31/01/2001
//****************************************************

var whitespace = " \t\n\r";

function isNatural(str) {
	var i;
	var c;
	var tmp = new String;
	if (str == null || str.length == null)
		return false;
	tmp = Trim(str);
	if (tmp.length == 0)
		return false;
	for (i=0;i<tmp.length;i++){
		c = tmp.charAt(i);
		if ( c < '0' || c > '9' )
			return false;
	}
	return true;		
}

function isReal(str) {
	var c;
	var tmp;
	var p;
	if ( str == null || str.length == null)
		return false;
	tmp = Trim(str);
	if (tmp.length == 0)
		return false;
	c = tmp.charAt(0);
	if ( c == '-' || c == '+' )
		tmp = tmp.substring(1,tmp.length);
	p = tmp.indexOf(',');
	if ( p == -1 )
		return isNatural(tmp);
	return isNatural(tmp.substring(0,p)) 
		&& isNatural(tmp.substring(p+1, tmp.length));
}

function LTrim(str) {
	var i;
	var inicio; //posicion desde donde no hay espacios
	if (str == null)
		return "";
	largo = str.length;
	inicio = 0;
	for (i=0; i<largo; i++) {
		c = str.charAt(i);
		if (c == ' ')
			inicio = i + 1;
		else
			break;
	}
	return str.substring(inicio,largo);
}

function RTrim(str) {
	var i;
	var fin; //posicion hasta donde no hay espacios
	if (str == null)
		return "";
	fin = str.length;
	for (i=fin-1; i>=0; i--) {
		c = str.charAt(i);
		if (c == ' ')
			fin = i;
		else
			break;
	}
	return str.substring(0,fin);
}

function Trim(str) {
	return(RTrim(LTrim(str)));
}












/**
 * DHTML date validation script for dd/mm/yyyy. 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 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("El formato de fecha debe ser: dd/mm/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 isEmail (s)
{
    if (isEmpty(s))
       if (isEmail.arguments.length == 1) return false;
       else return (isEmail.arguments[1] == true);
    if (isWhitespace(s)) return false;
    var i = 1;
    var sLength = s.length;
    while ((i < sLength) && (s.charAt(i) != "@"))
    { i++
    }
    if ((i >= sLength) || (s.charAt(i) != "@")) return false;
    else i += 2;

    while ((i < sLength) && (s.charAt(i) != "."))
    { i++
    }

    if ((i >= sLength - 1) || (s.charAt(i) != ".")) return false;
    else return true;
}

//* funcion para revisar el ingreso de campos vacios
function isEmpty(s)
{   return ((s == null) || (s.length == 0))
}
function isWhitespace (s)
{   var i;
    if (isEmpty(s)) return true;
    for (i = 0; i < s.length; i++)
    {
        var c = s.charAt(i);
        // si el caracter en que estoy no aparece en whitespace,
        // entonces retornar falso
        if (whitespace.indexOf(c) == -1) return false;
    }
    return true;
}