//Ajax
// Esta função instancia o objeto XMLHttpRequest
function openAjax()
{
	var ajax;
	try
	{
		ajax = new XMLHttpRequest();
	}
	catch(ee)
	{
		try
		{
			ajax = new ActiveXObject("Msxml2.XMLHTTP");
		}
		catch(e)
		{
			try
			{
				ajax = new ActiveXObject("Microsoft.XMLHTTP");
			}
			catch(E)
			{
				ajax = false;
			}
		}
	}

	return ajax;
}