var isNN = (navigator.appName.indexOf("Netscape")!=-1);

function autoTab(input,len, e) {
	var keyCode = (isNN) ? e.which : e.keyCode;
	var filter = (isNN) ? [0,8,9] : [0,8,9,16,17,18,37,38,39,40,46];

	var sel = document.selection;
	if (sel.type == 'Text')
		return false;
		
	if (input.name=='bd_mo' && input.value > 12)
	return false;
	if (input.name=='bd_day' && input.value > 31)
	return false;
	if (input.name=='bd_yr' && input.value.length == len) {
		if (input.value < 1900) {
			input.value = '';
			return false;
		}
		var curdate = new Date()
		var year = curdate.getYear()
		if (input.value >= (year - 17)) {
			var bday = new Date()
			var bdyear = Math.round(input.value) + 18;
			bday.setFullYear(bdyear, document.signup.bd_mo.value, document.signup.bd_day.value);
			tminus = bday.getFullYear();
			alert("Pimpwar is open to adults age 18 and older. Please come back and see us in "+tminus+".");
			return false;
		} else if (year - input.value > 99) {
			xy = document.signup.gender[0].checked;
			xx = document.signup.gender[1].checked;
			if (xy){n = " grandpops";}else if (xx) {n = " granny";}else{n = "";}
			alert("Sorry"+n+", but we are sure at your age you wouldn't want to venture any further!");
			return false;
		}
	}

	rev = /[^0-9]/
	str = input.value;
	input.value = str.replace(rev, "");

	re = /[0-9]+/g
	x = re.test(input.value);
	
	if (!x) {
		return false;
	}

	if(input.value.length >= len && !containsElement(filter,keyCode)) {
		input.value = input.value.slice(0, len);
		input.form[(getIndex(input)+1) % input.form.length].focus();
	}

	function containsElement(arr, ele) {
		var found = false, index = 0;
		while(!found && index < arr.length)
		if(arr[index] == ele)
		found = true;
		else
		index++;
		return found;
	}

	function getIndex(input) {
		var index = -1, i = 0, found = false;
		while (i < input.form.length && index == -1)
		if (input.form[i] == input)index = i;
		else i++;
		return index;
	}
	return true;
}