function CNFcheckEmail (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;    
}

function CNFcheckDate (dateStr) {
	var error = "";
	if (dateStr == "") {
	   error = "You didn't enter a date.\n";
	}
	else
	{
		var datePat = /^(\d{1,2})(\/|-)(\d{1,2})\2(\d{2}|\d{4})$/;
		
		// To require a 4 digit year entry, use this line instead:
		// var datePat = /^(\d{1,2})(\/|-)(\d{1,2})\2(\d{4})$/;
		
		var matchArray = dateStr.match(datePat); // is the format ok?
		if (matchArray == null) {
			error = "Start date is not in a valid format. Please use MM/DD/YYYY format.\n"
		}
		else
		{
			month = matchArray[1]; // parse date into variables
			day = matchArray[3];
			year = matchArray[4];
			if (month < 1 || month > 12) { // check month range
				error = "Month must be between 1 and 12.\n";
			}
			if (day < 1 || day > 31) {
				error = "Day must be between 1 and 31.\n";
			}
			if ((month==4 || month==6 || month==9 || month==11) && day==31) {
				error = "Month "+month+" doesn't have 31 days\n"
			}
			if (month == 2) { // check for february 29th
				var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
				if (day>29 || (day==29 && !isleap)) {
					error = "February " + year + " doesn't have " + day + " days\n";
			   }
			}
		}
	}
return error;
}

// number only - strip out delimiters

function CNFcheckNumber (strng,variable) {
var error = "";
if (strng == "") {
   error = "You didn't enter a " + variable + ".\n";
}

var stripped = strng.replace(/[\(\)\.\-\ ]/g, ''); //strip out acceptable non-numeric characters
    if (isNaN(parseInt(stripped))) {
       error = "The " + variable + " contains illegal characters.";
  
    }
return error;
}

// number only - strip out delimiters

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

var stripped = strng.replace(/[\(\)\.\-\ ]/g, ''); //strip out acceptable non-numeric characters
    if (isNaN(parseInt(stripped))) {
       error = "The budget figure contains illegal characters: please use only numbers.";
  
    }
return error;
}

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

function CNFcheckPhone (strng) {
var error = "";
if (strng == "") {
   error = "You didn't enter a phone number.\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;
}

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

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

var stripped = strng.replace(/[\(\)\.\-\ ]/g, ''); //strip out acceptable non-numeric characters
    if (isNaN(parseInt(stripped))) {
       error = "The zip code contains illegal characters.";
  
    }
    if (!(stripped.length == 5)) {
	error = "The zip code is the wrong length. Use only your 5 digit zip code.\n";
    } 
return error;
}


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

function CNFcheckPassword (strng) {
var error = "";
if (strng == "") {
   error = "You didn't enter a password.\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 CNFcheckUsername (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 CNFisEmptyName(strng, mess) {
var error = "";

  if (strng.length == 0) {

	if(!(mess)){
		CNFisEmpty(strng);
	}else{
    	error = "The \"" + mess + "\" field has not been filled in.\n";
	}
  }
return error;	  
}

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

// was textbox altered

function CNFisDifferent(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 CNFcheckRadio(checkvalue) {
var error = "";
   if (!(checkvalue)) {
       error = "Please check a radio button.\n" + checkvalue;
    }
return error;
}

// valid selector from dropdown list

function CNFcheckDropdownName(choice, mess) {
var error = "";
    if (choice == 0) {
    error = "You didn't choose a \"" + mess + "\".\n";
    }    
return error;
}

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