Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user’s experience. For more help http://xhr.spec.whatwg.org/
Un XMLHttpRequest sincrono en o filo prencipal ye obsoleto porque puede tener efectos negativos en a experiencia de l'usuario final. Ta mas aduya, mire-se http://xhr.spec.whatwg.org/