function RetornaHttpRequest() {
	var http_request = false;

	if (window.XMLHttpRequest) { /* Mozilla, Safari,... */
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) {
			http_request.overrideMimeType('text/xml');
			/* See note below about this line */
		}
	} else if (window.ActiveXObject) { /* IE */
		try { http_request = new ActiveXObject("Msxml2.XMLHTTP"); } 
		catch (e) {
			try { http_request = new ActiveXObject("Microsoft.XMLHTTP"); } 
			catch (e) {}
		}
	}

	if (!http_request) {
		alert('Giving up :( Cannot create an XMLHTTP instance');
		return false;
	}
	
	return http_request;
}

function NoCache(strURL) {
	var NoCache = new Date().getTime(); 
	if(strURL.indexOf('?')==-1){var Separador='?'} else {var Separador='&'}
	return Separador + 'NoCache=' + NoCache
}


function ColunasAnteriores(DataSource) {
	http_request = RetornaHttpRequest();
	http_request.onreadystatechange = alertColunasAnteriores;
	http_request.open('GET', DataSource + NoCache(DataSource), true);
	http_request.send(null);
}


function alertColunasAnteriores() {
	if(document.getElementById('DivColunasAnteriores')) {
		var strHTML = '';
		var ObjContent = document.getElementById('DivColunasAnteriores');
		if (http_request.readyState == 1 || http_request.readyState == 2) {
			ObjContent.innerHTML = '<div align="center"><img src="/imagens_site/loading.gif" border="0"></div>'
		} else if (http_request.readyState == 4) {
			if (http_request.status == 200) {
				ObjContent.innerHTML = http_request.responseText;
			} else { 
				ObjContent.innerHTML = 'Existe um problema nesta p&aacute;gina.';
			}
		}
	}
}