function isEmailAddress(strValue)
{
	var j,strTemp;
	strTemp = strValue;
	if (strTemp != '') 
	{
	var nCountC = 0;
	for ( j = 0; j< strTemp.length; j++ ){
	c = strTemp.charAt(j);
	if ( !( c>='0' && c<='9' || c>='a' && c<='z' || c>='A' && c<='Z' || c == '@' || c == '.' || c =='_' || c =='-') ) 
		return false;
		if (c == '@') nCountC  = nCountC + 1;
	}
	if (nCountC != 1)return false;
	if (strTemp.charAt(strTemp.length - 1) == '@' || strTemp.charAt(0) == '@' || strTemp.charAt(strTemp.length - 1) == '.' || strTemp.charAt(0) == '.')
	return false;
	}
	return true;
}

function checkEmailInput(obj,sMessage)
{
    if(!isEmailAddress(obj.value))
    {
        alert(sMessage);
        obj.focus();
        return false;
    }
    return true;
}

function checkAllUnAll(bCheck,nameCheckBox)
{
    var arrObjCheck=new Array();
    var index=0;
    var inps = document.forms[0].getElementsByTagName("input");
    for(var i=0; i < inps.length; i++)
    if(inps[i].id==nameCheckBox)
    {
        arrObjCheck[index++]=inps[i];
    }
        
    for(var i=0; i < arrObjCheck.length; i++)
    {
        arrObjCheck[i].checked=bCheck;
    }
}

//tuannd them 01/10/2008: ham kiem tra ngay kieu dd/mm/yyyy

function checkDate(obj,sMessage)
{
    if (!isValidDate(obj.value))
    {
        alert(sMessage);
        obj.focus();
        return false;
    }
    return true;
}
function isValidDate(value) {
    var dateString = value;
    if (dateString == "") {
        return true;
    }
    if (dateString.length != 10 || dateString.charAt(2) != '/' ||  dateString.charAt(5) != '/') {
        return false;
    }
    var day = trimZeroes(dateString.substring(0, 2));
    var month = trimZeroes(dateString.substring(3, 5));
    var year = trimZeroes(dateString.substring(6, 10));

    if (!(isPositiveInteger(month) && isPositiveInteger(day) && isPositiveInteger(year))) {
        return false;
    }
    if (parseInt(month) <= 0 || parseInt(month) > 12) {
        return false;
    }
    var maxFebDays = 28;
    if (isLeapYear(year)) {
        maxFebDays = 29;
    }
    var daysInMonth = new Array(31, maxFebDays, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
    if (parseInt(day) <= 0 || parseInt(day) > daysInMonth[parseInt(month) - 1]) {
        return false;
    }
    return true;
}

function isLeapYear(yr) {
    if ((parseInt(yr) % 4 == 0 && parseInt(yr) % 100 != 0) || parseInt(yr) % 400 == 0) {
        return true;
    }
    return false;
}

function isNonNegativeInteger(value) {
    if (isNaN(value)) {
        return false;
    }
    if (parseInt(value) < 0) {
        return false;
    }
    return true;
}

function isPositiveInteger(value) {
    if (isNaN(value)) {
        return false;
    }
    if (parseInt(value) <= 0) {
        return false;
    }
    return true;
}

function trimZeroes(value) {
    var length = value.length;
    for (i = 0; i < length; i++) {
        if (value.charAt(i) != '0') {
            break;
        }
    }
    if (i >= length) {
        return 0;
    }
    value = value.substring(i, length);
    return value;
}


function checkInt(obj,sMessage)
{
    if (obj.value == "") {
        return true;
    }
    if (isNaN(obj.value)) {
        alert(sMessage);
        obj.focus();        
        return false;
    }
    if (parseInt(obj.value) <= 0) {
        alert(sMessage);
        obj.focus();
        return false;
    }
    return true;
}
//end tuannd 01/10/2008