javascript - window.pageYOffset or just pageYOffset? / X + IEnumber+ pageYOffset / X support? -
1) i've noticed (at least in chrome) there no difference in output of these two:
pageyoffset; window.pageyoffset;
they both access same global return same - difference between these calls , better use?
my current suspicion: suspect look-for-variables implementation, idea window.pageyoffset direct access window object pageyoffset property whereas runing pageyoffset "slowly" every scope deep top , finaly finds in (super)global scope. think? did make tests?
2) ienumber+ supports window.pageyoffset / or pageyoffset ?
2) answer: mdn says ie<9 doesnt support those, answer 2) problably ie9+ (no surprise)
source: @blender & https://developer.mozilla.org/en-us/docs/web/api/window.scrolly
using window.
prefix faster because, mentioned, there no lookup. won't mess if define local variable called 'pageyoffset' because still @ window.pageyoffset.
i because it's more explicit , there less confusion.
edit: difference lookup, obviously.
Comments
Post a Comment