function objetoAjax(){
	var xmlhttp=false;
		try {
			xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
		}catch(e){
			try {
				xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
			}catch(E){
				xmlhttp = false;
			}
		}
if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
	  xmlhttp = new XMLHttpRequest();
  	}
  	return xmlhttp;
}

function revisarUsuario(){
  	divResultado = document.getElementById('checarUs');
   	user=document.registro_uno.usuario.value;
    ajax=objetoAjax();
	ajax.open("POST", "checarUs.php",true);
  	ajax.onreadystatechange=function() {
  		if (ajax.readyState==4) {
 		  divResultado.innerHTML = ajax.responseText
		}
  	}
  ajax.setRequestHeader("Content-Type","application/x-www-form-urlencoded");

  
  ajax.send("usuario="+user)
}

function checarContra(){
  	divResultado = document.getElementById('checarContra');
   	contra=document.registro_uno.contrasena.value;
	repcontra=document.registro_uno.rep_contrasena.value;
	
    ajax=objetoAjax();
	ajax.open("POST", "checarUs.php",true);
  	ajax.onreadystatechange=function() {
  		if (ajax.readyState==4) {
 		  divResultado.innerHTML = ajax.responseText
		}
  	}
  ajax.setRequestHeader("Content-Type","application/x-www-form-urlencoded");

  
  ajax.send("contrasena="+contra+"&rep_contrasena="+repcontra)
}