function send_ajax(url, parametros, funcao_ok)
{	
	try
	{	
		ajax = new XMLHttpRequest();
	}
	catch(e1)
	{
		try
		{
			ajax = new ActiveXObject('Msxml2.XMLHTTP');
		}
		catch(e2)
		{
			try
			{
				ajax = new ActiveXObject('Microsoft.XMLHTTP');
			}
			catch(e3)
			{
				alert('Browser sem suporte a AJAX !');
				ajax = false;
			}
		}
	}
	
	if (ajax)
	{
		ajax.open('POST', url, true);				
		ajax.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
		ajax.onreadystatechange = function ()
											{
												if (ajax.readyState == 4)
												{
													funcao_ok(ajax.responseText);
												}
											};
		ajax.send(parametros);
	}
}