I am using Unity version 2019.4.19f1 to make webgl build. After making the build I resize the unity canvas using these line below (in UnityLoader.js inside "DOMContentLoaded" eventlistner):

let unityContent = document.getElementById('unityContainer');
var tempWidth = window.innerWidth - ( window.innerWidth * 0.0001 );
var tempHeight = window.innerHeight;
unityContent.style.width = tempWidth+'px';
unityContent.style.height = tempHeight+'px';

But when I open this in a browser in Portrait mode I get a black screen, while when I open it in landscape mode then it is working fine. And this happens in devices having screen size 6 inches and above only. On devices having smaller height the portrait mode opens fine and no black screen is shown.

Also if I hard code the tempHeight to 1500px then even portrait mode shows the canvas instead of black screen but then there is empty space on the screen above and below the canvas. What's more troubling is that the same code was working fine a few months ago in other projects.

Can Anyone Help me out with this please? Have been stuck on this for some time now.