// functions that return true or false indicating validity of a specific 
// type of input 
//
// to use, call the function and pass it input.
// 
// document.myForm.onSubmit = function() {
//	if (!isValidPhoneNumber(document.myForm.phone_number.value)) {
//		alert("the phone number you entered sucks!");
//		return false;
//	}
//	return true;
// }


function isValid(type, str) {
	var temp = str.trim();
	
	if (type == 'text') {
		return temp.length > 0;
		
	} else if (type == 'num') {
		return isValidNumber(temp);
	
	} else if (type == 'phone') {
		return isValidPhoneNumber(temp);
	
	} else if (type == 'email') {
		return isValidEmailAddress(temp);
	
	} else if (type == 'zip') {
		return isValidZipCode(temp);
	
	} else if (type == 'cc') {
		return isValidCCNumber(temp);
	
	} else if (type == 'usd') {
		return isValidUSDAmount(temp);
	}
	return false;
}


function isValidNumber(s, min, max) {
	var temp = s.replace(/\D/g, "");
	return temp.length > 0; // && temp >= min && temp <= max;
}

function isValidPhoneNumber(s) {
	var temp = s.replace(/\D/g, "");
	return temp.length > 9 && temp.length < 26;
}

function isValidZipCode(s) {
	var temp = s.replace(/\D/g, "");
	return temp.match(/^\d{5}$|^\d{9}$/) != null;
}

function isValidSelectBox(o) {
	if (o.options.length == 0) 
		return true;
	return (o.options[o.selectedIndex].value != "_none_" && 
			o.options[o.selectedIndex].value.trim() != "");
}

function isValidEmailAddress(s) {
	var temp = s.replace(/\s/g, "");
	return (temp.match(/^[\w\.\-]+\x40[\w\.\-]+\.\w{2,4}$/)) && 
			temp.charAt(0) != "." && !(temp.match(/\.\./));
}

function isValidCCNumber(s) {
	var temp = s.replace(/\D/g, "");
	
	// implement full mod-10 check?
	
	// simple check for plausible Visa or Mastercard
	return temp.match(/^(4|5)\d{15}$/) != null;
}

function isValidUSDAmount(s) {
	var temp = s.replace(/[^\d.]/g, "");
	return temp.match(/^\d+\.\d\d$/) != null;
}





// masking functions - attempt to parse and reformat 
// element's values as a specific datatype
// to use, tack them to the form field's onblur handler.
// document.myForm.phone_number.onblur = phoneFieldBlurHandler	
//   -> this field will now mask for phone numbers onblur
function textFieldBlurHandler() {
	this.value = this.value.trim()
}

function numFieldBlurHandler() {
	this.value = this.value.replace(/\D/g, "")
}

function dateFieldBlurHandler() {
	var d = new Date(this.value)
	if (!isNaN(d)) {
		// if the user didn't specify the century/millenium,
		// then assume the present.
		if (this.value.search(/\d{3}/) == -1) 
			d.setYear(Math.floor((new Date()).getFullYear() / 100) * 100 + d.getFullYear() % 100);

		this.value = d.getHumanDateString()
	}
}

function timeFieldBlurHandler() {
	var t = new Time(this.value)
	if (!isNaN(t)) this.value = t.getHumanTimeString()
}

function emailFieldBlurHandler() {
	this.value = this.value.replace(/\s/g, "")
}

function phoneFieldBlurHandler() {
	var temp = this.value.replace(/\D/g, "")

	if (temp.length > 9 && temp.length < 26) 
		if (temp.length == 10) {
			this.value = "(" + temp.substring(0,3) + ") " 
			this.value += temp.substring(3,6) + "-" + temp.substring(6,10)
		}
}

function zipFieldBlurHandler() {
	var temp = this.value.replace(/\D/g, "")
	this.value = temp;

	if (temp.length == 5 || temp.length == 9) { 
		if (temp.length == 5) this.value = temp
		else this.value = temp.substring(0,5) + "-" + temp.substring(5,9)
	}
}

function ccFieldBlurHandler() {
	var temp = this.value.replace(/\D/g, "");

	if (temp.length == 16) {
		this.value = temp.substring(0,4) + "-" + temp.substring(4,8);
		this.value += "-" + temp.substring(8,12) + "-" + temp.substring(12,16);
	}
}

function usdFieldBlurHandler() {
	var temp = this.value.replace(/[^\d.]/g, "");
	
	if (temp.match(/^\d+$/)) 
		temp += '.00';
	if (temp.match(/^\./)) 
		temp = '0' + temp;
	if (temp.match(/\.$/)) 
		temp += '00';
	else if (temp.match(/\.\d$/)) 
		temp += '0';
	this.value = temp;
}




// convenience function.
// attaches textFieldBlurHandler to the onblur event 
// of every text or textarea element in f
// var myForm = document.myForm
// attachAllTextHandlers(myForm) 
//		-> every text element in myForm now will call 
//		   textFieldBlurHandler (above) onblur
function attachAllTextHandlers(f) {
	var el
	for (var i = 0; (el = f.elements[i]); i++) {
		if (el.type == "text" || el.type == "textarea") 
			el.onblur = textFieldBlurHandler
	}
}





// Extensions to the Date class:
// var myDate = new Date();
// myDate.getMonthName(); -> "February"
// myDate.getHumanDateString(); -> "29 February 2000"
// myDate.getHumanTimeString(); -> "4:00 pm"


// returns the name of the month
Date.prototype.getMonthName = function() {
	return ["January","February","March","April","May","June","July","August",
			"September","October","November","December"][this.getMonth()]
}


// returns a nicely formatted date string
Date.prototype.getHumanDateString = function() {
	return this.getDate() + " " + this.getMonthName() + " " + this.getFullYear()
}


// returns a nicely formatted time string
Date.prototype.getHumanTimeString = function() {
	var h = this.getHours()
	var m = this.getMinutes()
	var t = h >= 12 ? "pm" : "am"

	if (h == 0) h = 24
	if (h > 12) h -= 12
	h = String(h)
	m = String(m)
	if (m.length == 1) m = "0" + m

	return h + ":" + m + " " + t
}





// Time is a wrapper class for the Date object
// it accepts a wide variety of strings representing the time
// and returns a date object representing the current date with the
// specified time.
//
// var myTime = new Time('4p');
// myTime now contains a date object representing today at 4PM.
//
// accepted formats include 4p, 4:p, 4:1p, 4:10p, 4:10pm, 16:00, 
// and a bunch more...

function Time(sTimeStr) {
	if (sTimeStr.trim() != "")
	{
		var a = sTimeStr.match(/\d{1,2}/g)
		var t = sTimeStr.match(/(am|pm|a|p)/ig)
		if (a) {
			var d = new Date()
			var h = a[0]
			var m = a[1] ? a[1] : 0;
			if (t) t = String(t[0]);
			if (t && t.charAt(0).toLowerCase() == "p") h = h % 12 + 12
			d.setHours(h)
			d.setMinutes(m)
			return d
		}
		return null
	}
}



// Extensions to the String class:
// var myStr = "  yomomma.mpg "
// myStr.trim() -> myStr now contains "hotdogs!"
// myStr.hasFileExtension(".mpg") -> true


// like Trim( ) in vbscript. removes trailing and 
// leading whitespace from a string
String.prototype.trim = function() {
	return this.replace(/^\s*|\s*$/g, "")
}


// determines whether or not a filename has one of the specified extensions
String.prototype.endsWith = function() {
	var bOk = false
	for (var i = 0; i < arguments.length; i++) {
		if (this.indexOf(arguments[i]) == this.length - arguments[i].length) {
			bOk = true
			break
		}
	}
	return bOk
}


// push is a quite useful method of arrays in newer 
// javascript implementations, but not in ie5-
Array.prototype.push = function(v) {
	this[this.length] = v
	return v
}