function isBlank(field){
	with (field){if (value==null||value==""){return true;}}
}
function validate_required(field,alerttxt){
	with (field){if (value==null||value==""){alert(alerttxt);return false}else {return true}}
}
function validate_email(field,alerttxt){
with (field){
	apos=value.indexOf("@")
	dotpos=value.lastIndexOf(".")
		if (apos<1||dotpos-apos<2) {alert(alerttxt);return false}else {return true}
	}
}
function validate_radio(btn,alerttxt) {
	with (btn){if (!checked){alert(alerttxt);return false}else {return true}}
}
function validate_form_ml(thisform) {
	with (thisform){if (validate_required(name,"Please enter a name")==false){name.focus();return false}}
	with (thisform){if (validate_required(email,"Please enter an email address")==false){email.focus();return false}}
}

function validate_form_rf(theForm) {
    var why = "";
    why += isEmpty(theForm.name.value,"Please enter your name.");
    why += checkEmail(theForm.email.value);
    why += isEmpty(theForm.address.value,"Please enter your address.");
    why += isEmpty(theForm.city.value,"Please enter your city.");
    why += isEmpty(theForm.state.value,"Please enter your state.");
    why += isEmpty(theForm.zip.value,"Please enter your zip.");
	for (i=0, n=theForm.exchange.length; i<n; i++) {
        if (theForm.exchange[i].checked) {
            var checkvalue = theForm.exchange[i].value;
            break;
        } 
    }
    why += checkRadio(checkvalue,"Please select an exchange option.");    
    why += isEmpty(theForm.explanation.value,"Please enter an explanation for your return.");	

    if (why != "") {
       alert(why);
       return false;
    }
return true;
}



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 (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;
}


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

function checkPassword (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 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,message) {
var error = "";
  if (strng.length == 0) {
     error = message + "\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,message) {
var error = "";
   if (!(checkvalue)) {
       error = message + "\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;
}