function Boletin(){
    txt="Correo Electrónico";
    if(document.getElementById("form_boletin")){
    
    input_=document.getElementById("form_boletin").getElementsByTagName("input")[0];
    boton=document.getElementById("form_boletin").getElementsByTagName("button")[0];
    emailpat = /^([a-zA-Z0-9])+([\.a-zA-Z0-9_-])*@([a-zA-Z0-9_-])+(\.[a-zA-Z0-9]+)+$/;
    
   	input_.onfocus=function(){
   	input_.style.color='#ffffff';
    if(input_.value==txt){
    input_.value="";
    }
    }
    
    input_.onblur=function(){
    if(input_.value==""){
    input_.style.color='#ffffff';
    input_.value=txt;
    }
    }
    boton.onmouseover=function(){
    //boton.parentNode.parentNode.style.backgroundColor="#990000";
    //boton.parentNode.getElementsByTagName("span")[0].style.backgroundPosition="0px -30px";
    boton.style.backgroundColor="#ffffff";
    boton.style.backgroundPosition="0px -28px";
    }
    boton.onmouseout=function(){
    //boton.parentNode.parentNode.style.backgroundColor="#cc0000";
    //boton.parentNode.getElementsByTagName("span")[0].style.backgroundPosition="0px 0px";
    boton.style.backgroundColor="#cc0000";
    boton.style.backgroundPosition="0px 0px";
    }
    boton.onclick=function(){
    if(emailpat.test(input_.value)){
    return true;
    }
    else if(input_.value=="Correo Electrónico" ){
    //location.href='http://desarrollo.kategora.com/formulario-de-registro-login.php?keepThis=true&TB_iframe=true&height=490&width=772';
    //alert("Debe introducir su dirección de Correo Electrónico");
    tb_show(null,"../formulario-de-registro-login.php?keepThis=true&TB_iframe=true&height=490&width=772",false);
    input_.focus();
    return false;
    }
    else{
    alert("El formato del email no es correcto");
    input_.focus();
		return false;
    }
    }
    }
    }