function isEmailAddr(email){
  var result = false;
  var theStr = new String(email);
  var index = theStr.indexOf("@");
  if (index > 0){
    var pindex = theStr.indexOf(".",index);
    if ((pindex > index+1) && (theStr.length > pindex+1))
	result = true;
  }
  return result;
}

function enableButton(name) {
	var enabled = document.getElementById(name + "_enabled");
	var disabled = document.getElementById(name + "_disabled");
	enabled.style.display = '';
	disabled.style.display = 'none';
}

function disableButton(name) {
	var enabled = document.getElementById(name + "_enabled");
	var disabled = document.getElementById(name + "_disabled");
	enabled.style.display = 'none';
	disabled.style.display = '';
}

function termsClicked() {
	var terms = document.getElementById("terms");
	if (terms.checked)
		enableButton("register");
	else
		disableButton("register");
}

function validRequired(formField,fieldLabel){
	var result = true;
	if (formField.value == ""){
		alert('Enter your ' + fieldLabel);
		formField.focus();
		result = false;
	}
	
	return result;
}

function validPassword(formField1,formField2){
	var result = true;	
	if (formField1.value != formField2.value){
		alert('Verify Password Incorrect');
		formField2.focus();
		result = false;
	}
	
	return result;
}

function allDigits(str){
   return inValidCharSet(str,"0123456789");
}

function inValidCharSet(str,charset){
	var result = true;
	for (var i=0;i<str.length;i++)
		if (charset.indexOf(str.substr(i,1))<0) {
			result = false;
			break;
		}
	
	return result;
}

function validEmail(formField,fieldLabel,required){
	var result = true;
	
	if (required && !validRequired(formField,fieldLabel))
		result = false;

	if (result && ((formField.value.length < 3) || !isEmailAddr(formField.value)) )	{
		alert('Enter a valid email address');
		formField.focus();
		result = false;
	}
   
  return result;

}

function validNum(formField,fieldLabel,required){
	var result = true;
	if (required && !validRequired(formField,fieldLabel)) result = false;
 	if (result) {
 		if (!allDigits(formField.value)){
 			alert('Enter a valid number');
			formField.focus();		
			result = false;
		}
	} 
	return result;
}


function validInt(formField,fieldLabel,required){
	var result = true;
	if (required && !validRequired(formField,fieldLabel)) result = false;
 	if (result){
 		var num = parseInt(formField.value);
 		if (isNaN(num)){
 			alert('Enter a valid number');
			formField.focus();		
			result = false;
		}
	} 
	return result;
}

function validDate(formField,fieldLabel,required){
	var result = true;
	if (required && !validRequired(formField,fieldLabel)) result = false;
 	if (result){
 		var elems = formField.value.split("/");
 		result = (elems.length == 3); // should be three components
 		if (result)	{
 			var month = parseInt(elems[0]);
  			var day = parseInt(elems[1]);
 			var year = parseInt(elems[2]);
			result = allDigits(elems[0]) && (month > 0) && (month < 13) &&
					 allDigits(elems[1]) && (day > 0) && (day < 32) &&
					 allDigits(elems[2]) && ((elems[2].length == 2) || (elems[2].length == 4));
 		}
  		if (!result){
 			alert('Enter a valid date "' + fieldLabel +'".');
			formField.focus();		
		}
	} 
	
	return result;
}