var request = false;
var campoHtml;

try {
    request = new XMLHttpRequest();
} catch (trymicrosoft) {
    try {
        request = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (othermicrosoft) {
        try {
            request = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (failed) {
            request = false;
        }
    }
}

function verificaUsuarioAjax(cod, campo){
	campoHtml = campo;
	if(cod != '' && cod.length > 5){
		document.getElementById('divlogin').innerHTML = '&nbsp;&nbsp;<img src="images/ajax_preloader.gif" />';
		var url = "user.jsp?user="+escape(cod);
        request.open("GET", url, true);
        request.onreadystatechange = updatePage;
        request.send(null);
	}else{
        campoHtml.value = '';
		campoHtml.className = 'formularios_pendentes';
		document.getElementById('divlogin').innerHTML = '&nbsp;&nbsp;Usuário inválido. Crie seu usuário de acesso ao portal.';
		usuario = false;
	}
}

function updatePage() {
    if (request.readyState == 4) {
        if (request.status == 200) {

            var conteudo = "";
            var response = request.responseText.split("|");

            conteudo = response[0];

            conteudo = conteudo.replace(/[\n\r]+/g, "");
            conteudo = conteudo.replace("   ","");

            if(conteudo.substring(17,21)=='ERRO'){
            	campoHtml.className = 'formularios_pendentes';
            	usuario = false;
            	document.getElementById('divlogin').innerHTML = '&nbsp;&nbsp;Este usuário já existe. Por favor digite outro.';

            } else {
            	campoHtml.className = 'formularios_ok';
            	document.getElementById('divlogin').innerHTML = '&nbsp;&nbsp;<img src="images/ok_loader.png"  />';
            	usuario = true;
            }

        }
    }
}