CSS

how to remove border on button click

.btnName{
	outline: none;
}

remove clicked button border

<button style="outline: none;"></button>

remove outline on button click

using outline:none; we can remove that border in chrome

for tailwind css :
outline-none 
focus:outline-none

how to remove border in outlinebutton

OutlinedButton(
    onPressed: () {},
    child: Text('Outlined button'),
    style: OutlinedButton.styleFrom(
      side: BorderSide(
         color: Colors.transparent,
      ),
    ),
  ),