function isValidEmail(email, required) {
    if (required==undefined) {   // if not specified, assume it's required
        required=true;
    }
    if (email==null) {
        if (required) {
            return false;
        }
        return true;
    }
    if (email.length==0) {  
        if (required) {
            return false;
        }
        return true;
    }
    if (! allValidChars(email)) {  // check to make sure all characters are valid
        return false;
    }
    if (email.indexOf("@") < 1) { //  must contain @, and it must not be the first character
        return false;
    } else if (email.lastIndexOf(".") <= email.indexOf("@")) {  // last dot must be after the @
        return false;
    } else if (email.indexOf("@") == email.length) {  // @ must not be the last character
        return false;
    } else if (email.indexOf("..") >=0) { // two periods in a row is not valid
	return false;
    } else if (email.indexOf(".") == email.length) {  // . must not be the last character
	return false;
    }
    return true;
}

function allValidChars(email) {
  var parsed = true;
  var validchars = "abcdefghijklmnopqrstuvwxyz0123456789@.-_";
  for (var i=0; i < email.length; i++) {
    var letter = email.charAt(i).toLowerCase();
    if (validchars.indexOf(letter) != -1)
      continue;
    parsed = false;
    break;
  }
  return parsed;
}

function formValidate() {

	if(document.form1.name.value == "")
	{
		alert("Name should not be empty.");
		document.form1.name.focus();
		return false;
	}
	if(document.form1.company.value == "")
	{
		alert("Company should not be empty.");	
		document.form1.company.focus();
		return false;
	}
	if(document.form1.desg.selectedIndex == 0)
	{
		alert("Designation should not be empty.");
		document.form1.desg.focus();
		return false;
	}
	if(document.form1.address.value == "")
	{
		alert("Address should not be empty.");
		document.form1.address.focus();
		return false;
	}
	if(document.form1.city.value == "")
	{
		alert("City should not be empty.");
		document.form1.city.focus();
		return false;
	}
	if(document.form1.zip.value == "")
	{
		alert("Zip code should not be empty.");
		document.form1.zip.focus();
		return false;
	}
	
	if(document.form1.txtTelephone.value == "")
	{
		alert("Telephone should not be empty.");
		document.form1.txtTelephone.focus();
		return false;
	}
	if(document.form1.txtFax.value == "")
	{
		alert("Fax should not be empty.");
		document.form1.txtFax.focus();
		return false;
	}
	if(document.form1.email.value == "")
	{
		alert("Email should not be empty.");
		document.form1.email.focus();
		return false;
	}
	if (! isValidEmail(form1.email.value)) 
       {
      		alert("Please enter a valid email address");
      		form1.email.focus();
      		form1.email.select();
      		return false;
       }	
	if(document.form1.nob.selectedIndex == 0)
	{
		alert("Nature of Business should not be empty.");
		document.form1.nob.focus();
		return false;
	}
}