function remove_value(id,this_value)
{
	if($(id).value == this_value)
	{
		$(id).value = '';
		/*$(id).style.textAlign = 'left';*/
	}
}

function set_value(id,this_value)
{
	if ($(id).value == '')
	{
		$(id).value = this_value;
		/*$(id).style.textAlign = 'right';*/
	}
}

function hide_value(id,this_value)
{
	if ($(id).value == '') 
	{
		$(id + '_show').innerHTML = this_value;
	}
	else 
	{
		$(id + '_show').innerHTML = this_value + ': ' + $(id).value;
	}
	$(id).type = 'hidden';
	$(id + '_show').style.display = 'block';
}

function show_value(id)
{
	$(id).type = 'text';
	$(id).focus();
	$(id + '_show').style.display = 'none';
}

function IsNumeric(sText)
{
	var ValidChars = "0123456789.";
	var IsNumber=true;
	var Char;

	for (i = 0; i < sText.length && IsNumber == true; i++)
	{ 
		Char = sText.charAt(i); 
		if (ValidChars.indexOf(Char) == -1) 
		{
			IsNumber = false;
		}
	}
	return IsNumber;
}

function change_price()
{
	if ($('number').value == '') var number = 0;
	else var number = $('number').value;
	
	var price_one = $('price_one').value;
	
	if (IsNumeric(number) && IsNumeric(price_one))
	{
		$('price').value='&#8364;' + (price_one * number);
		$('price_show').innerHTML= '&#8364;' + (price_one * number);
	}
	else
	{
		$('price').value = '';
		$('price_show').innerHTML='TOTAL PRICE';
	}
}

function change_magazine(year,number)
{
	if ($('issue').value!='') 
	{
		$('magazine_' + $('year').value + '_' + $('issue_selected').value).className = 'magazine';
	}
	$('magazine_' + year + '_' + number).className = 'magazine_selected';
}

function change_checkbox(id)
{
	var imageid = id + '_image';
	if ($(id).value == 'true')
	{
		$(imageid).src = 'http://danskmagazine.com/image/checkbox.gif';
		$(id).value = 'false';
		/*$('number').disabled = '';*/
		change_price();
	}
	else
	{
		$(imageid).src = 'http://danskmagazine.com/image/checkbox_selected.gif';
		$(id).value = 'true';
		$('number').value = 'NUMBER OF ISSUES';
		/*$('number').disabled = 'disabled';*/
		$('price').value= '&#8364;' + $('subscription_price').value;
		$('price_show').innerHTML= '&#8364;' + $('subscription_price').value;
	}
}

function check_blog_values()
{
	if($('name').value=='NAME')
	{
		alert('Please enter your name');
		return false;
	}
	
	if($('text').value=='TEXT MESSAGE')
	{
		alert('Please enter your text message');
		return false;
	}
	return true;
}

function check_back_issues_values()
{
	if($('year').value=='')
	{
		alert('Please enter year');
		return false;
	}
	
	if($('issue').value=='')
	{
		alert('Please enter issue no.');
		return false;
	}
	
	if($('number').value=='NUMBER OF ISSUES')
	{
		alert('Please enter number of issues');
		return false;
	}

	if($('name').value=='NAME')
	{
		alert('Please enter your name');
		return false;
	}
	
	if($('address').value=='ADDRESS')
	{
		alert('Please enter your address');
		return false;
	}
	
	if($('city').value=='CITY')
	{
		alert('Please enter your city');
		return false;
	}
	
	if($('postalcode').value=='POSTAL CODE')
	{
		alert('Please enter your postal code');
		return false;
	}
	
	if($('country').value=='COUNTRY')
	{
		alert('Please enter your country');
		return false;
	}
	
	if($('email').value=='E-MAIL')
	{
		alert('Please enter your e-mail');
		return false;
	}

	return true;
}

function check_buy_values()
{
	if($('number').value=='NUMBER OF ISSUES')
	{
		alert('Please enter number of issues');
		return false;
	}
	
	if($('name').value=='NAME')
	{
		alert('Please enter your name');
		return false;
	}
	
	if($('address').value=='ADDRESS')
	{
		alert('Please enter your address');
		return false;
	}
	
	if($('city').value=='CITY')
	{
		alert('Please enter your city');
		return false;
	}
	
	if($('postalcode').value=='POSTAL CODE')
	{
		alert('Please enter your postal code');
		return false;
	}
	
	if($('country').value=='COUNTRY')
	{
		alert('Please enter your country');
		return false;
	}
	
	if($('email').value=='E-MAIL')
	{
		alert('Please enter your e-mail');
		return false;
	}

	return true;
}

function check_competition_values()
{
	if($('name').value=='NAME')
	{
		alert('Please enter your name');
		return false;
	}
	
	if($('address').value=='ADDRESS')
	{
		alert('Please enter your address');
		return false;
	}
	
	if($('city').value=='CITY')
	{
		alert('Please enter your city');
		return false;
	}
	
	if($('postalcode').value=='POSTAL CODE')
	{
		alert('Please enter your postal code');
		return false;
	}
	
	if($('country').value=='COUNTRY')
	{
		alert('Please enter your country');
		return false;
	}
	
	if($('email').value=='E-MAIL')
	{
		alert('Please enter your e-mail');
		return false;
	}
	
	return true;
}