function initAjaxForm()
{
	var forms = document.getElementsByTagName('form');
	var uid = 0;
	for (var i = 0; i < forms.length; i++) 
		if(hasClass(forms[i], 'ajaxForm'))
		{
			if(forms[i].id == '')
			{
				do
				{
					uid++;
				}
				while(document.getElementById('ajaxForm' + uid) != null);
				forms[i].id = 'ajaxForm' + uid;
			}
			forms[i].action = "javascript:submitAjaxForm('"+forms[i].id+"');";
		}
}

function submitAjaxForm(id)
{
	var obj = document.getElementById(id);
	var args = new Object();
	var required = new Object();

	// add all input values to args
	var inputs = obj.getElementsByTagName('input');
	for (var i = 0; i < inputs.length; i++)
	{
		if(inputs[i].name == null)
			continue;
		if(hasClass(inputs[i], 'required'))
			if(required[inputs[i].name] == null)
				required[inputs[i].name] = true;
		if(inputs[i].name == 'ajaxFormCompleteDiv')
		{
			obj.ajaxFormComplete = document.getElementById(inputs[i].value);
			continue;
		}
		switch (inputs[i].type)
		{
			case 'text':
			case 'password':
			case 'hidden':
			{
				args[inputs[i].name] = inputs[i].value;
				break;
			}
			case 'radio':
			case 'checkbox':
			{
				if(inputs[i].checked)
					args[inputs[i].name] = inputs[i].value;
				break;
			}
		}
	}
	
	// add all select values to args
	var selects = obj.getElementsByTagName('select');
	for (var i = 0; i < selects.length; i++)
	{
		if(hasClass(selects[i], 'required'))
			if(required[selects[i].name] == null)
				required[selects[i].name] = true;
		args[selects[i].name] = selects[i].value;
	}
	
	// add all textarea values to args
	var textareas = obj.getElementsByTagName('textarea');
	for (var i = 0; i < textareas.length; i++)
	{
		if(hasClass(textareas[i], 'required'))
			if(required[textareas[i].name] == null)
				required[textareas[i].name] = true;
		args[textareas[i].name] = textareas[i].value;
	}
	
	// temp remove sepcial ajaxFormSubject field so it's notinargs list
	var ajaxFormSubject = args['ajaxFormSubject']
	args['ajaxFormSubject'] = null;
	
	// add args list to args for PHP to know which are vars from the form
	var argsList = '';
	for(var i in args)
		if(i != 'ajaxFormSubject')
			argsList += i + ',';
	argsList = argsList.substring(0, argsList.length - 1);
	args['argsList'] = argsList;
	
	// restore subject
	args['ajaxFormSubject'] = ajaxFormSubject;
	
	// add required list to args for PHP to know which are required vars from the form
	var requiredList = '';
	for(var i in required)
		requiredList += i + ',';
	requiredList = requiredList.substring(0, requiredList.length - 1);
	args['requiredList'] = requiredList;
	
	// add field to know its submitted
	args['ajaxForm'] = '1';

	// build POST string
	var postString = '';
	for(var i in args)
		postString += i + '=' + encodeURIComponent(args[i]) + '&';

	// if query string isn't empty, take last '&' off
	if(postString != '')
		postString = postString.substring(0, postString.length - 1);
	
	// send off to PHP
	var ajaxObj = navigator.appName == "Microsoft Internet Explorer" ? new ActiveXObject("Microsoft.XMLHTTP") : new XMLHttpRequest();
	ajaxObj.open('POST', 'ajaxForm.php?', true);
	ajaxObj.onreadystatechange = function()
	{
		if(ajaxObj.readyState == 4) // if success
			ajaxFormCallback(ajaxObj.responseText, obj);
	};
	ajaxObj.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
	ajaxObj.send(postString);
}

function ajaxFormCallback(response, form)
{
	if(response == 'done')
	{
		form.style.display = 'none';
		if(form.ajaxFormComplete != null)
			form.ajaxFormComplete.style.display = 'block';
	}
	
	// errors
	else
	{
		resetAjaxFormErrors(form);

		var inputs = form.getElementsByTagName('input');
		var selects = form.getElementsByTagName('select');
		var textareas = form.getElementsByTagName('textarea');

		// make invalid fields stand out
		var vars = response.split(',');
		for(var i = 0; i < vars.length; i++)
		{
			for(var j = 0; j < inputs.length; j++)
				if(inputs[j].name == vars[i])
					inputs[j].className = trim(inputs[j].className + ' ajaxFormError');
			for(var j = 0; j < selects.length; j++)
				if(selects[j].name == vars[i])
					selects[j].className = trim(selects[j].className + ' ajaxFormError');
			for(var j = 0; j < textareas.length; j++)
				if(textareas[j].name == vars[i])
					textareas[j].className = trim(textareas[j].className + ' ajaxFormError');
		}
	}
}

function resetAjaxFormErrors(form)
{
	var inputs = form.getElementsByTagName('input');
	for(var i = 0; i < inputs.length; i++)
		if(hasClass(inputs[i], 'ajaxFormError'))
			inputs[i].className = inputs[i].className.replace('ajaxFormError', '')
	
	var selects = form.getElementsByTagName('select');
	for(var i = 0; i < selects.length; i++)
		if(hasClass(selects[i], 'ajaxFormError'))
			selects[i].className = selects[i].className.replace('ajaxFormError', '')
	
	var textareas = form.getElementsByTagName('textarea');
	for(var i = 0; i < textareas.length; i++)
		if(hasClass(textareas[i], 'ajaxFormError'))
			textareas[i].className = textareas[i].className.replace('ajaxFormError', '')
}



function hasClass(obj, clazz)
{
	var classes = obj.className.split(' ');
	for (var i = 0; i < classes.length; i++) 
		if (classes[i] == clazz) 
			return true;
	return false;
}

function trim(str)
{
	return str.replace(/^\s+|\s+$/g,"");
}

// setup onload
if (window.addEventListener)
	window.addEventListener('load', initAjaxForm, false);
else if (window.attachEvent)
	window.attachEvent('onload', initAjaxForm);
else
	window.onload = initAjaxForm;