function borra(){if(enLlamada)return false;$("#pantalla").val(($("#pantalla").val()).substring(0,($("#pantalla").val()).length-1));return false}function addZero(a){if(a<10){a="0"+a}return a}function cambiaHora(){var a=new Date();var e=document.getElementById("demo");var d=addZero(a.getHours());var c=addZero(a.getMinutes());var b=addZero(a.getSeconds());$("#reloj").html(d+":"+c+":"+b)}setInterval(function(){cambiaHora()},100);$(function(){$("#tiempoLlamada").hide()})