xhr headers for loading
xhr headers for loading

xhr.status == 200 || xhr.status == 201 || xhr.status == 202 || xhr.status == 0  
--> 201, 202 valid response, from cache
--> 0 status when loading from file:/// <-- it doesn't mean failed

xhr.readyState == 3 -- Loading :: increase loading by 10%
mistic100/Photo-Sphere-Viewer,mistic100/Photo-Sphere-Viewer,mistic100/Photo-Sphere-Viewer,marcin1337/Photo-Sphere-Viewer,marcin1337/Photo-Sphere-Viewer