Using Device Orientation on page load

Question

I am trying to grab the alpha, beta and gamma coordinates through the deviceorientation event.

My code:

window.addEventListener('deviceorientation', function(event) {
  alert(event.alpha + ' : ' + event.beta + ' : ' + event.gamma);
});

JS Fiddle: https://jsfiddle.net/myL17nzt/

This works great to constantly grab the coordinates as the device moves, but I would like to just grab the coordinates on page load and not make it listen for movement. I tried changing window.addEventListener to window.onload, but that didn't do the trick.

Any ideas how I could accomplish this?

Thanks!

Answer 1

It would be better to have the listener remove itself.

function deviceOrientation(event) {
  alert(event.alpha + ' : ' + event.beta + ' : ' + event.gamma);
  window.removeEventListener('deviceorientation', deviceOrientation);
}
window.addEventListener('deviceorientation', deviceOrientation);

This way you don't have it being called for events that you don't care about. Some libraries have a function called once that removes the event listener after the first event occurence.