How to make a transparent HTML button?

To get rid of the outline when clicking, add outline:none

JSFiddle example

button {
    background-color: transparent;
    background-repeat: no-repeat;
    border: none;
    cursor: pointer;
    overflow: hidden;
    outline: none;
}

button {
    background-color: transparent;
    background-repeat: no-repeat;
    border: none;
    cursor: pointer;
    overflow: hidden;
    outline: none;
}

<button>button</button>