var el_fe, el_ft;
var fetext = "your email address";
var fttext = "your message";

function toggleFeedback()	{
	var el = document.getElementById('feedback');
	if(el.style.display == 'none')	{
		el.style.display = 'block';
	} else {
		el.style.display = 'none';
	}
}

function initPage(toggle)	{
	el_fe = document.getElementById('formemail');
	el_ft = document.getElementById('formtext');
	if ((el_fe.value == '' || el_fe.value == fetext) &&
	    (el_ft.value == '' || el_ft.value == fttext))
	{
		if (toggle==1)	{
			toggleFeedback();
		}
	}
}

function clearfe()	{
	if (el_fe)	{
		if (el_fe.value == fetext) el_fe.value = "";
	}
}

function clearft()	{
	if (el_ft)	{
		if (el_ft.value == fttext) el_ft.value = "";
	}
}

function trim(sString)	{
	while (sString.substring(0,1) == ' ')	{
		sString = sString.substring(1, sString.length);
	}
	while (sString.substring(sString.length-1, sString.length) == ' ')	{
		sString = sString.substring(0,sString.length-1);
	}
	return sString;
}





function verifyForm()
{
	var emailstr = document.getElementById("formemail").value;
	var textstr = document.getElementById("formtext").value;
	var r;
	if (emailCheck(emailstr) == false) return false;
	if (textCheck(textstr) == false) return false;
	
	/* we're sending, so disable the submit button and return true. */
	var sub = document.getElementById('submit');
	sub.setAttribute('value', 'Sending...');
	sub.setAttribute('disabled', true);
	return true;
}


<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->

function emailCheck (emailStr)
{
	var emailPat=/^(.+)@(.+)$/
	var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
	var validChars="\[^\\s" + specialChars + "\]"
	var quotedUser="(\"[^\"]*\")"
	var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
	var atom=validChars + '+'
	var word="(" + atom + "|" + quotedUser + ")"
	var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
	var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")
	
	var matchArray=emailStr.match(emailPat)
	if (matchArray==null) {
		alertInvalidEmail();
		return false
	}
	var user=matchArray[1]
	var domain=matchArray[2]
	
	if (user.match(userPat)==null) {
			alertInvalidEmail();
	    return false
	}
	
	var IPArray=domain.match(ipDomainPat)
	if (IPArray!=null) {
		  for (var i=1;i<=4;i++) {
		    if (IPArray[i]>255) {
					alertInvalidEmail();
					return false
		    }
	    }
	    return true
	}
	
	var domainArray=domain.match(domainPat)
	if (domainArray==null) {
		alertInvalidEmail();
	  return false
	}
	
	var atomPat=new RegExp(atom,"g")
	var domArr=domain.match(atomPat)
	var len=domArr.length
	if (domArr[domArr.length-1].length<2 || 
	    domArr[domArr.length-1].length>3) {
			alertInvalidEmail();
			return false
	}
	if (len<2) {
		alertInvalidEmail();
		return false
	}
	
	// If we've gotten this far, everything's valid!
	return true;
}

function textCheck (text)
{
	if (text.length < 5)
	{
		alert ('You must include a message to send.');
		return false;
	}
	return true;
}

function alertInvalidEmail()
{
	alert ('This email address does not appear to be valid.\nPlease check it and try again.');
}