function isblank(s) {
for (var i= 0; i < s.length; i ++) {
var c = s.charAt(i);
if (( c != ' ') && (c != '\n') && (c != '\t')) return false;
}
return true;
}

function checkEmail(str) {

		var atSymbol="@"
		var dotSymbol="."
		var atPos=str.indexOf(atSymbol)
		var strLen=str.length
		var dotPos=str.indexOf(dotSymbol)
		if (str.indexOf(atSymbol)==-1){
		   alert("Please enter a valid email address.")
		   return false
		}

		if (str.indexOf(atSymbol)==-1 || str.indexOf(atSymbol)==0 || str.indexOf(atSymbol)==strLen){
		   alert("Please enter a valid email address.")
		   return false
		}

		if (str.indexOf(dotSymbol)==-1 || str.indexOf(dotSymbol)==0 || str.indexOf(dotSymbol)==strLen){
		    alert("Please enter a valid email address.")
		    return false
		}

		 if (str.indexOf(atSymbol,(atPos+1))!=-1){
		    alert("Please enter a valid email address.")
		    return false
		 }

		 if (str.substring(atSymbol-1,atSymbol)==dotSymbol || str.substring(atPos+1,atPos+2)==dotSymbol){
		    alert("Please enter a valid email address.")
		    return false
		 }

		 if (str.indexOf(dotSymbol,(atPos+2))==-1){
		    alert("Please enter a valid email address.")
		    return false
		 }
		
		 if (str.indexOf(" ")!=-1){
		    alert("Please enter a valid email address.")
		    return false
		 }

 		 return true					
	}

function checkCharacters(str,validChars) {

for (i=0; i < str.length; i++) {
if(validChars.indexOf(str.charAt(i))<0){ 
return false;
}
}
}

<!--
function _validatePageOne() {

  var form = document.registerform;
  if (form.WebUserTitle.selectedIndex==0) {
  alert('Please select a title.');
  return false;
  }
  if (form.WebUserFirstName.value=="") {
  alert('Please enter a first name.');
  form.WebUserFirstName.focus();
  return false;
  }
  var validList = "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.";
  if (checkCharacters(form.WebUserFirstName.value,validList)==false) {
  alert('Please enter only letters for your first name.');
  return false;
  }
  if (checkCharacters(form.WebUserMiddleInitial.value,validList)==false) {
  alert('Please enter only letters for your middle name.');
  return false;
  }
    
  if (form.WebUserLastName.value=="") {
  alert('Please enter a last name.');
  form.WebUserLastName.focus();
  return false;
  }
  if (checkCharacters(form.WebUserLastName.value,validList)==false) {
  alert('Please enter only letters for your last name.');
  return false;
  }
  
  if (form.WebUserEmail.value=="") {
  alert('Please enter an email address.');
  form.WebUserEmail.focus();
  return false;
  }
  if (checkEmail(form.WebUserEmail.value)==false) return false;
  
  if (form.tmpPassword.value=="") {
  alert('Please enter a password.');
  form.tmpPassword.focus();
  return false;
  }
  var pwStr=form.tmpPassword.value;
  if (pwStr.length<=5) {
  alert('Password must be at least 6 characters.');
  form.tmpPassword.focus();
  return false;
  }
  return true;
}

function _validatePageOneA() {
  var form = document.registerform;
  if (form.SuggestedUsername.selectedIndex==0) {
  alert('Please choose a username or choose Other from the list and type a new one.');
  return false;
  }
  else {
  if (form.SuggestedUsername.options[form.SuggestedUsername.selectedIndex].text=="Other") {
  if (form.OtherUserName.value=="") {
  alert('Please specify the other username.');
  return false;
    }
  }
  }
  
  if (form.WebUserEmail.value=="") {
  alert('Please enter an email address.');
  form.WebUserEmail.focus();
  return false;
  }
  if (checkEmail(form.WebUserEmail.value)==false) return false;
  
  if (form.tmpPassword.value=="") {
  alert('Please enter a password.');
  form.tmpPassword.focus();
  return false;
  }
  var pwStr=form.tmpPassword.value;
  if (pwStr.length<=5) {
  alert('Password must be at least 6 characters.');
  form.tmpPassword.focus();
  return false;
  }
  return true;
}

function _validatePageTwo() {
  var form = document.registerform;
  
  if (form.WebUserQuestion.value=="") {
  alert('Please enter a secret question.');
  form.WebUserQuestion.focus();
  return false;
  }
  if (form.WebUserAnswer.value=="") {
  alert('Please enter a secret answer.');
  form.WebUserAnswer.focus();
  return false;
  }
  if (form.WebUserStreetAddress.value=="") {
  alert('Please enter a Street address.');
  form.WebUserStreetAddress.focus();
   return false;
  }
    if (form.WebUserCity.value=="") {
  alert('Please enter a city.');
  form.WebUserCity.focus();
   return false;
  }
  if (form.WebUserState.value=="") {
  alert('Please enter a state.');
  form.WebUserState.focus();
   return false;
  }
  if (form.WebUserZip.value=="") {
  alert('Please enter a zip/postal code.');
  form.WebUserZip.focus();
   return false;
  }
  if (form.WebUserCountry.selectedIndex==0) {
  alert('Please enter a country.');
   return false;
  }
  if (form.WebUserAreaCode.value=="") {
  alert('Please enter an area code.');
  form.WebUserAreaCode.focus();
   return false;
  }
  if (form.WebUserPhoneNumber1.value=="") {
  alert('Please enter a phone number.');
  form.WebUserPhoneNumber1.focus();
   return false;
  }
  return true
}