how to place a focus in css code example

Example 1: input focus css default

/* This removes all focus effects */
element:focus {
	outline-style: none;
	box-shadow: none;
	border-color: transparent; 
}

Example 2: css focus change color

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