// email

function checkEmail (strng, errmsg) {
var error="";
if (strng == "") {
   error = "Please fill in the '"+ errmsg +"' field.\n";
}

    var emailFilter=/^.+@.+\..{2,3}$/;
    if (!(emailFilter.test(strng))) { 
       error = "Please enter a valid email address.\n";
    }
    else {
//test email for illegal characters
       var illegalChars= /[\(\)\<\>\,\;\:\\\"\[\]]/;
         if (strng.match(illegalChars)) {
          error = "The email address contains illegal characters.\n";
       }
    }
return error;    
}


// phone number - strip out delimiters and check for 10 digits

function checkPhone (strng, errmsg) {
var error = "";
if (strng == "") {
   error = "Please fill in the '"+ errmsg +"' field.\n";
}

var stripped = strng.replace(/[\(\)\.\-\ ]/g, ''); //strip out acceptable non-numeric characters
    if (isNaN(parseInt(stripped))) {
       error = "The phone number contains illegal characters.";
  
    }
    //if (!(stripped.length == 10)) {
	//error = "The phone number is the wrong length. Make sure you included an area code.\n";
    //} 
return error;
}

// Declaring required variables
var digits = "0123456789";
// non-digit characters which are allowed in phone numbers
var phoneNumberDelimiters = "-";
// characters which are allowed in international phone numbers
var validWorldPhoneChars = phoneNumberDelimiters ;
// Minimum no of digits in an international phone no.
var minDigitsInIPhoneNumber = 10;

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 trim(s)
{   var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not a whitespace, append to returnString.
    for (i = 0; i < s.length; i++)
    {   
        // Check that current character isn't whitespace.
        var c = s.charAt(i);
        if (c != " ") returnString += c;
    }
    return returnString;
}
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++)
    {   
        // Check that current character isn't whitespace.
        var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}

function checkInternationalPhone(strPhone){
var bracket=3
var errormsg = "Please enter the phone number in xxx-xxx-xxxx format.\n";
strPhone=trim(strPhone)
if(strPhone.indexOf("+")>1) return errormsg
if(strPhone.indexOf("-")!=-1)bracket=bracket+1
if(strPhone.indexOf("(")!=-1 && strPhone.indexOf("(")>bracket)return errormsg
var brchr=strPhone.indexOf("(")
if(strPhone.indexOf("(")!=-1 && strPhone.charAt(brchr+2)!=")")return errormsg
if(strPhone.indexOf("(")==-1 && strPhone.indexOf(")")!=-1)return errormsg
s=stripCharsInBag(strPhone,validWorldPhoneChars);
if (isInteger(s) && s.length >= minDigitsInIPhoneNumber && strPhone.length >= 12 )
{ return "";  }
else
{ return errormsg; }
}


// password - between 6-8 chars, uppercase, lowercase, and numeral

function checkPassword (strng, errmsg) {
var error = "";
if (strng == "") {
   error = "Please fill in the '"+ errmsg +"' field.\n";
}

    var illegalChars = /[\W_]/; // allow only letters and numbers
    
    if ((strng.length < 6) || (strng.length > 8)) {
       error = "The password is the wrong length.\n";
    }
    else if (illegalChars.test(strng)) {
      error = "The password contains illegal characters.\n";
    } 
    else if (!((strng.search(/(a-z)+/)) && (strng.search(/(A-Z)+/)) && (strng.search(/(0-9)+/)))) {
       error = "The password must contain at least one uppercase letter, one lowercase letter, and one numeral.\n";
    }  
return error;    
}    


// username - 4-10 chars, uc, lc, and underscore only.

function checkUsername (strng) {
var error = "";
if (strng == "") {
   error = "You didn't enter a username.\n";
}


    var illegalChars = /\W/; // allow letters, numbers, and underscores
    if ((strng.length < 4) || (strng.length > 10)) {
       error = "The username is the wrong length.\n";
    }
    else if (illegalChars.test(strng)) {
    error = "The username contains illegal characters.\n";
    } 
return error;
}       


// non-empty textbox

function isEmpty(strng, errmsg) {
var error = "";
  if (strng.length == 0) {
     error = "Please fill in the '"+ errmsg+"' field.\n"
  }
return error;	  
}

// was textbox altered

function isDifferent(strng) {
var error = ""; 
  if (strng != "Can\'t touch this!") {
     error = "You altered the inviolate text area.\n";
  }
return error;
}

// exactly one radio button is chosen

function checkRadio(checkvalue, errmsg) {
var error = "";
   if (!(checkvalue)) {
       error = "Please Choose '"+ errmsg +"'.\n";
    }
return error;
}

// valid selector from dropdown list

function checkDropdown(choice, errmsg) {
var error = "";
    if (choice == 0) {
    error = "Please fill in the '"+ errmsg+"' field.\n";
    }    
return error;
}

function checkCheckBox(chk, errmsg){
 var error = "";
  if (chk.checked != 1) {
    error = "You must check the '" + errmsg + "' checkbox.\n";
	}
return error;
}