// email

function checkEmail (strng, errmsg) {
var error="";
if (strng == "") {
   error = errmsg + " You didn't enter an email address.\n";
}

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


// ZIP Code - strip out delimiters and check for 5 Characters

function checkZipCode (tempcontrol, errmsg) {
var error = "";
if (tempcontrol.value == "") {
   error = errmsg + " You didn't enter a ZIP Code.\n";
}

    var stripped = tempcontrol.value.replace(/[\(\)\.\-\ ]/g, ''); //strip out acceptable non-numeric characters
    if (!(stripped.length == 5)) {
	error = errmsg + " The ZIP Code is the wrong length. You must have five characters.\n";
    } 
return error;
}


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

function checkPhone (strng, errmsg) {
var error = "";
if (strng == "") {
   error = errmsg + " You didn't enter a phone number.\n";
}

var stripped = strng.replace(/[\(\)\.\-\ ]/g, ''); //strip out acceptable non-numeric characters
    if (isNaN(parseInt(stripped))) {
       error = errmsg + " The phone number contains illegal characters.";
  
    }
    if (!(stripped.length == 10)) {
	error = errmsg + " The 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 (strng, errmsg) {
var error = "";
if (strng == "") {
   error = errmsg + " You didn't enter a password.\n";
}

    var illegalChars = /[\W_]/; // allow only letters and numbers
    
    if ((strng.length < 6) || (strng.length > 8)) {
       error = errmsg + " The password is the wrong length.\n";
    }
    else if (illegalChars.test(strng)) {
      error = errmsg + " The password contains illegal characters.\n";
    } 
    else if (!((strng.search(/(a-z)+/)) && (strng.search(/(A-Z)+/)) && (strng.search(/(0-9)+/)))) {
       error = errmsg + " 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, errmsg) {
var error = "";
if (strng == "") {
   error = errmsg + " You didn't enter a username.\n";
}


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


// non-empty textbox

function isEmpty(strng, errmsg) {
var error = "";
  if (strng.length == 0) {
     error = errmsg
  }
return error;	  
}

// was textbox altered

function isDifferent(strng, errmsg) {
var error = ""; 
  if (strng != "Can\'t touch this!") {
     error = errmsg;
  }
return error;
}

// check multiple radio buttons for one selection

function checkRadioButtons(checkbutton, errmsg) {
var checkvalue = "";
var error = "";

    for (i=0, n=checkbutton.length; i<n; i++) {
        if (checkbutton[i].checked) {
            checkvalue = checkbutton[i].value;
            break;
        } 
    }
    error = checkRadio(checkvalue, errmsg);
return error;	
}

// exactly one radio button is chosen

function checkRadio(checkvalue, errmsg) {
var error = "";
   if (!(checkvalue)) {
       error = errmsg;
    }
return error;
}

// check multiple check box buttons for one selection

function checkCheckBoxButtons(checkbutton, errmsg) {
var checkvalue = "";
var error = "";

    for (i=0, n=checkbutton.length; i<n; i++) {
        if (checkbutton[i].checked) {
            checkvalue = checkbutton[i].value;
            break;
        } 
    }
    error = checkCheckBox(checkvalue, errmsg);
return error;	
}

// exactly one checkbox is chosen

function checkCheckBox(checkvalue, errmsg) {
var error = "";
   if (!(checkvalue)) {
       error = errmsg;
    }
return error;
}

// exactly one checkbox is chosen

function checkOther(tempcontrol, temptext, errmsg) {
var error = "";
   if (tempcontrol.checked==true && temptext.value=="") {
       error = errmsg;
    }
return error;
}
// valid selector from dropdown list

function checkDropdown(choice, errmsg) {
var error = "";
    if (choice == 0) {
    error = errmsg;
    }    
return error;
}