function attachEventListener(target, eventType, functionRef, capture) {
    if (typeof target.addEventListener != "undefined") {
        target.addEventListener(eventType, functionRef, capture);
    } else if (typeof target.attachEvent != "undefined") {
        target.attachEvent("on" + eventType, functionRef);
    } else {
        return false;
    }
    return true;
}


function target_blank() {
	if (!document.getElementsByTagName) return;
	var i;
	var enlaces = document.getElementsByTagName("a");
	var cuantos = enlaces.length;
	for (i = 0; i < cuantos; i++) {
		if (enlaces[i].getAttribute("href") && enlaces[i].getAttribute("rel") == "external") enlaces[i].target = "_blank";
	}
}

	
function mostrarOcultar(){
	if(document.getElementById('registrar').style.display == 'none'){
		document.getElementById('registrar').style.display = 'block';
		document.getElementById('botreg').style.backgroundImage="none";
		document.getElementById('botreg').style.backgroundColor="#000000"; 
		document.getElementById('botreg').style.color="#E9AF2F"; 
	} else {
		document.getElementById('registrar').style.display = 'none';
		document.getElementById('botreg').style.backgroundImage="url(images/boton_naranja.gif)";
		document.getElementById('botreg').style.backgroundColor="transparent"; 
	}
       

	}
attachEventListener(window, "load", mostrarOcultar, false);
attachEventListener(window, "load", target_blank, false);