Answers for "how to change button focus color css"

css focus change color

<style>
.dabutton:focus {
    background-color:yellow;
}
</style>
<button class="dabutton"></button> // <-- usage

css keep focus color on div after click

$('button').on('click', function(){
    $('button').removeClass('selected');
    $(this).addClass('selected');
});