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;
            }
               
        }  
    }   
}