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;
    }
	
    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 validateMultiple(obj){
	var result = 0;
	for(var i=0; i<obj.length; i++){
		if(obj[i].checked==true) result = 1
	}
	if(result == 1) {
		return true;
	}else{
		return false;
	}
}

function checkLicense() {
	if (document.licenseform.name.value == '' || document.licenseform.jobtitle.value == '' || document.licenseform.organisation.value == '' || document.licenseform.address.value == '' || document.licenseform.email.value == '' || document.licenseform.telephone.value == '' || validateMultiple(document.licenseform.organisationtype) == false) {
		alert("Please ensure all the fields are filled in");
		return false;
	}else if (! isValidEmail(document.licenseform.email.value)) {
        	alert("Please enter a valid email address");
        	return false;
	}else if ((document.licenseform.organisationtype[10].checked == true && document.licenseform.organisationtype_other.value == '') || (document.licenseform.organisationmember[5].checked == true && document.licenseform.organisationmember_other.value == '')) {
        	alert("You have selected 'other', please enter details in the 'other' box.");
        	return false;
	}else if (document.licenseform.licenseagree.checked == false) {
        	alert("You must agree to the terms of the license agreement");
        	return false;
    }else{
		return true;
	}
}



function valForm() {
	if (document.downloadform.surname.value == '' || document.downloadform.organisation.value == '' || document.downloadform.address1.value == '' || document.downloadform.county.value == '' || document.downloadform.email.value == '') {
		alert("Please fill in the fields marked by an asterisk.");
		return false;
	}else{
		if (! isValidEmail(document.downloadform.email.value)) {
        	alert("Please enter a valid email address");
        	return false;
    	}else{
			return true;
		}
	}
}