window.screen.width do not work on ios devices?

I have sphere animation on my site, for laptop, tablet and mobile I m using different sizes of sphere. Here you can see conditions of every type of device:

Laptop:
var screen_size = window.screen.width;
if(screen_size < 1025){
    false;
}else{
    sphere animation code;
}
Tablet:
var screen_size = window.screen.width;
if(screen_size >= 1025  || screen_size  < 668){
    false;
}else{
    sphere animation code;
}
Mobile:
var screen_size = window.screen.width;
if((screen_size > 667)){
    false;
}else{
    sphere animation code;
}

If I use one script separately its – works, other operation system – its works. I think suppose main problem in “window.screen.width”.

Here you an see my site with full code: thesevenwang