How to Zoom In And Zoom Out Button Continuously Using CSS

A button can be made zoom in and zoom out continuously using @keyframes in CSS. Below is html and css code for a pop up and pop in button.

HTML

<a href="javascript:void()" class="m-auto d-table linktomenu"><img src="img/menu-icon.png" alt="Menu" height="60"></a>

CSS

@keyframes linktomenu{
    0% {
        transform: scale(1,1);
    }
    50% {
        transform: scale(1.3,1.3);
    }
    100% {
        transform: scale(1,1);
    }
}
.linktomenu img {
    animation: linktomenu 1s infinite ;
}

Thus, you can make the zoom in and zoom out button automatically and continuously.