// email

function checkEmail (strng) {
	var error="";
	if (strng == "") {
   	error = "You didn't enter an email address.\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 (string1,string2) {
var error = "";
if (string1 == "") {
   error = "You didn't enter a phone number.\n";
}

var stripped = string1.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 " + string2 + " phone number is the wrong length. Make sure you included an area code.\n";
    } 
return error;
}


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

function checkPassword (string1,string2) {
	var error = "";
	if (string1 == "") {
   	error = "You didn't enter a password.\n";
	}

    var illegalChars = /[\W_]/; // allow only letters and numbers
    
    if ((string1.length < 6) || (string1.length > 8)) {
       error = "The password must be between 6 and 8 characters long.\n";
    }
    else if (illegalChars.test(string1)) {
      error = "The password can contain only letters and numbers.\n";
    } 
    else if (!((string1.search(/(a-z)+/)) && (string1.search(/(A-Z)+/)) && (string1.search(/(0-9)+/)))) {
       error = "The password must contain at least one uppercase letter, one lowercase letter, and one numeral.\n";
    }
	if (error == "")
		if (string1 != string2)
			error = "Please make sure the password values are the same.\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 must be between 4 and 10 characters long.\n";
    }
    else if (illegalChars.test(strng)) {
    error = "The username contains illegal characters.\n";
    } 
return error;
}       

function isValidNumber(num)
{
	var s = parseInt(num);
	if (isNaN(s) || s == "")
		return false;
	else
		return true;
}

// non-empty textbox

function isEmpty(strng, fieldname) {
var error = "";
  if (strng.length == 0) {
     error = "The mandatory text area " + fieldname + " has not been filled in.\n"
  }
return error;	  
}

function isSelected(cbox,msg)
{
	var error ="";
	if (!cbox.checked)
		error = "Please select " + msg + " checkbox\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) {
var error = "";
   if (!(checkvalue)) {
       error = "Please check a radio button.\n";
    }
return error;
}

// valid selector from dropdown list

function checkDropdown(choice) {
var error = "";
    if (choice == 0) {
    error = "You didn't choose an option from the drop-down list.\n";
    }    
return error;
}

function IsNumeric(sText)

{
   var ValidChars = "0123456789.";
   var IsNumber=true;
   var Char;

 
   for (i = 0; i < sText.length && IsNumber == true; i++) 
   { 
      Char = sText.charAt(i); 
      if (ValidChars.indexOf(Char) == -1) 
      {
         IsNumber = false;
      }
   }
	return IsNumber;
}