xs hidden bootstrap code example
Example 1: display sm none
Hidden on all .d-none
Hidden only on xs .d-none .d-sm-block
Hidden only on sm .d-sm-none .d-md-block
Hidden only on md .d-md-none .d-lg-block
Hidden only on lg .d-lg-none .d-xl-block
Hidden only on xl .d-xl-none
Visible on all .d-block
Visible only on xs .d-block .d-sm-none
Visible only on sm .d-none .d-sm-block .d-md-none
Visible only on md .d-none .d-md-block .d-lg-none
Visible only on lg .d-none .d-lg-block .d-xl-none
Visible only on xl .d-none .d-xl-block
Example 2: how to support xs in bootstrap 4
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">