// start tab switching
function modulate( tab,mod ) {
	mods = new Array( "mod1","mod2","mod3" );
	for ( i = 0; i < mods.length; i++ ) {
		state = "none";
		if ( mods[i] == mod ) {
			state = "block";
		}
		document.getElementById( mods[i] ).style.display = state;
	}
	tablynx = document.getElementById( "tabs" ).getElementsByTagName( "a" );
	for ( t = 0; t < tablynx.length; t++ ) {
		tablynx[t].className = "";
	}
	tab.className = "tabon";
	tab.blur();
}
// end tab switching




// start form validation 

function validateFormOnSubmit(theForm) {
	var reason = "";
	reason += validateFirstName(theForm.firstname);
	reason += validateLastName(theForm.lastname);
	reason += validateEmail(theForm.email);
	reason += validatePhone(theForm.phone);
  
	if ( reason != "" ) {
		alert(reason);
		return false;
	}	
	return true;
}

function validateEmpty(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#a9e97a'; 
        error = "The required field has not been filled in.\n"
    } else {
        fld.style.background = '#fff';
    }
    return error;  
}


function validateFirstName(fld) {
    var error = "";
    var illegalChars = /\W/; // allow letters, numbers, and underscores
 
    if (fld.value == "") {
        fld.style.background = '#a9e97a'; 
        error = " Please enter a first name.\n";
    } else if ((fld.value.length < 2) || (fld.value.length > 30)) {
        fld.style.background = '#a9e97a'; 
        error = "The name is the wrong length.\n";
    } else if (illegalChars.test(fld.value)) {
        fld.style.background = '#a9e97a'; 
        error = "The name contains illegal characters.\n";
    } else {
        fld.style.background = '#fff';
    }
    return error;
}


function validateLastName(fld) {
    var error = "";
    var illegalChars = /\W/; // allow letters, numbers, and underscores
 
    if (fld.value == "") {
        fld.style.background = '#a9e97a'; 
        error = "Please enter a last name.\n";
    } else if ((fld.value.length < 2) || (fld.value.length > 30)) {
        fld.style.background = '#a9e97a'; 
        error = "The name is the wrong length.\n";
    } else if (illegalChars.test(fld.value)) {
        fld.style.background = '#a9e97a'; 
        error = "The name contains illegal characters.\n";
    } else {
        fld.style.background = '#fff';
    }
    return error;
}

function trim(s) {
  return s.replace(/^\s+|\s+$/, '');
}

function validateEmail(fld) {
    var error="";
    var tfld = trim(fld.value);                        // value of field with whitespace trimmed off
    var emailFilter = /^[^@]+@[^@.]+\.[^@]*\w\w$/ ;
    var illegalChars= /[\(\)\<\>\,\;\:\\\"\[\]]/ ;
   
    if (fld.value == "") {
        fld.style.background = '#a9e97a';
        error = "Please enter an email address.\n";
    } else if (!emailFilter.test(tfld)) {              //test email for illegal characters
        fld.style.background = '#a9e97a';
        error = "Please enter a valid email address.\n";
    } else if (fld.value.match(illegalChars)) {
        fld.style.background = '#a9e97a';
        error = "The email address contains illegal characters.\n";
    } else {
        fld.style.background = '#fff';
    }
    return error;
}


function validatePhone(fld) {
    var error = "";
    var stripped = fld.value.replace(/[\(\)\.\-\ ]/g, '');    

	if (fld.value != "") {
		// do nothing;
		if (isNaN(parseInt(stripped))) {
			error = "The phone number contains illegal characters.\n";
			fld.style.background = '#a9e97a';
			return error;
		} else if (!(stripped.length == 10)) {
			error = "The phone number is the wrong length. Make sure you included an area code.\n";
			fld.style.background = '#a9e97a';
			return error;
		}
	}
	return error;
}






// end form validation