function acertaDominio() {

	var dominio = document.getElementById('dominio').value;

   if (document.form.username.value.length==0) {
      return;
   }

   if (document.form.username.value.toLowerCase().indexOf('@' + dominio) < 0) {
      resetaDominioUsername();
      document.form.username.value += "@" + dominio;
   }
}

function resetaDominioUsername() {
   if (document.form.username.value.indexOf('@')>-1) {
      document.form.username.value = document.form.username.value.substring(0,document.form.username.value.indexOf('@'));
   }
}

function inicioUsername() {

	var dominio = document.getElementById('dominio').value;

   if (document.form.username.value=="seu login@" + dominio) {
      document.form.username.value="";
   }
}

<!--
var erro = '';
var campousername = "E-mail";
var campopassword = "Senha";

function enviaForm(){

        if(validaCampo('username') && validaCampo('password') ) {
        		
                document.forms[0].submit();
         		return true;       
         }//if
         
	return false;
         
}

function validaCampo(campo){

        if(dg(campo).value=='') {
                alert('O campo "'+eval("campo"+campo)+'" precisa ser preenchido!');
                dg(campo).focus();
                return false;
        }else{
                return true;
        }
}

function dg($) {
        return eval("document.forms[0]." + $);
}

function $(o){
        return document.getElementById(o);
}

function carrega_erro(){

	if(erro!=null) {
	
		document.getElementById("msgerro").style.display = 'block';
    	document.getElementById("msgerro").innerHTML= unescape(erro);
    	
    }
    
}

function carrega_erro2(){
	document.getElementById("migrar").style.display = 'none';
	if(erro!=null) {
		
		document.getElementById("msgerro").style.display = 'block';
    	document.getElementById("msgerro").innerHTML= unescape(erro);
    	
    }
     if(erro=='migrar') {
		
		document.getElementById("migrar").style.display = 'block';
		document.getElementById("box").style.display = 'none';
		document.getElementById("msgerro").style.display = 'none';
    }
    
}

var arrParam = [];
var endereco = location.href;

if(endereco.indexOf("?") > -1){
    var qs = endereco.substring(endereco.indexOf("?")+1, endereco.length);
    var arrvlr = qs.split("&");
    for(i in arrvlr){
        param = arrvlr[i];
        var _auxarr = param.split("=");
        arrParam.push({"nome" : _auxarr[0], "valor" :_auxarr[1]});
    }
}

function getParam(paramName){
    for(i in arrParam){
        if(arrParam[i].nome == paramName){
            return arrParam[i].valor;
        }
    }
    return null;
}

function autenticar(frm) {
   if (frm.username.value.indexOf('@')<=-1) {
      alert('Por favor, digite seu e-mail completo');
      return false;
   } else {
   	var dominio = frm.username.value.substring(frm.username.value.indexOf('@') + 1);
   	frm.dominio.value = dominio;
   	frm.action = "http://authmail." + dominio + "/Autenticacao/autenticacao";
   }
}

erro = getParam('erro');