/**
* @brief checks a specified from for validity
* @return true .. form is sufficiently and correctly filled out; false .. it's not
*/
function CheckForm(form_elem)
{
	return true;
	for(var i = 0; i < form_elem.elements.length; i++)
	{
		var elem = form_elem.elements[i];
		alert(elem.getAttribute('class'));
		if((elem.getAttribute('class') != null) && elem.getAttribute('class').match(/\brequired\b/))
		{
			alert(elem.value);
			return false;
			if(elem.value == '')
			{
				alert("Bitte füll alle benötigten Felder aus!");
				return false;
			}
		}
	}
	return true;

	if(document.email_form.isrobot.checked == true)
	{
		alert('Roboter werden nicht bedient!');
		return false;
	}
	if(CheckTextInput(document.email_form.yyname) == false)
	{
		document.email_form.yyname.focus();
		return false;
	}
	if(CheckEmailInput(document.email_form.zznospam) == false)
	{
		document.email_form.zznospam.focus();
		return false;
	}
	if(CheckTextInput(document.email_form.vvtext) == false)
	{
		document.email_form.vvtext.focus();
		return false;
	}
	alert('E-Mail versendet!');
	return true;
}


/**
* @brief checks whether a text input field is empty or not
* @return true .. filled; false .. empty
*/
function CheckTextInput(form_elem)
{
	if(form_elem.value.match(/^\s*$/))
	{
		form_elem.style.borderColor = 'red';
		form_elem.style.borderStyle = 'solid';
		return false;
	}
	else
	{
		form_elem.style.border = '';
		return true;
	}
}


/**
* @brief checks whether an email input field has a valid url or not
* @return true .. valid; false .. invalid
*/
function CheckEmailInput(form_elem)
{
	if(form_elem.value.match(/^[a-z0-9\._%\+]+@[a-z0-9\.]+$/))
	{
		form_elem.style.border = '';
		return true;
	}
	else
	{
		form_elem.style.borderColor = 'red';
		form_elem.style.borderStyle = 'solid';
		return false;
	}
}


/**
* @brief checks whether an url input field has a valid url or not
* @return true .. valid; false .. invalid
*/
function CheckUrlInput(form_elem)
{
	if(form_elem.value.match(/^(http:\/\/)?(www\.)?[a-z0-9-%\.\/]+$/))
	{
		form_elem.style.border = '';
		return true;
	}
	else
	{
		form_elem.style.borderColor = 'red';
		form_elem.style.borderStyle = 'solid';
		return false;
	}
}


/**
* @brief toggles between block and none display using an id
*/
function ToggleId(object_id)
{
	if(document.getElementById(object_id).style.display == "none")
	{
		document.getElementById(object_id).style.display = "block";
	}
	else
	{
		document.getElementById(object_id).style.display = "none";
	}
}