HTML5 viewport not working

Spent days on this. I wanted to set my html5 canvas to the page height and width. Worked ok on my pc but failed to work correctly on my mobile. Then I revoved the ".0" in the "1.0" in my viewport metatag. So much for blindly copying examples, thinking they must be correct. Or the standard has changed over the years.
[meta name="viewport" content="width=device-width, initial-scale=1.0" /] failed to work on my mobile device.
But worked just fine and all I did was remove the ".0" at the end.