/*
Creates and returns an instance of an xmlHttpRequest object

@param	none

@return xmlHttpRequest object
*/
function new_xmlhttp()
{
	var ajax = false;
	
	// branch for native XMLHttpRequest object
	if(window.XMLHttpRequest) 
	{
		ajax = new XMLHttpRequest();
	} 
	// branch for IE/Windows ActiveX version
	else if(window.ActiveXObject) 
	{
		ajax = new ActiveXObject("Msxml2.XMLHTTP");
	}
	
	return ajax;
}

function validate_field(input_name, input_value, d, s)
{
	var ajax = new_xmlhttp();

	ajax.onreadystatechange = function() 
	{
		
		if(ajax.readyState == 4)
		{
			if ( ajax.responseText )
			{
				document.getElementById(input_name + '_error').className = 'content error_visible';
				document.getElementById(input_name + '_error').innerHTML = ajax.responseText;
			}
			else
			{
				document.getElementById(input_name + '_error').className = 'content error_hidden';
			}
		}
	}
	
	input_value = encodeURIComponent(input_value);
	vars = "single_input=" + input_name + "&" + input_name + "=" + input_value + "&d=" + d + "&s=" + s;
	
	//alert(vars);
	
	ajax.open("POST", '/includes/validate.field.php', true);
	
	ajax.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
	
	ajax.send(vars);
}