<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
* {box-sizing: border-box;}
.img-zoom-container {
position: relative;
}
.img-zoom-lens {
position: absolute;
border: 1px solid #d4d4d4;
</style>
<script>
function imageZoom(imgID, resultID) {
var img, lens, result, cx, cy;
img = document.getElementById(imgID);
result = document.getElementById(resultID);
/*create lens:*/
lens = document.createElement("DIV");
lens.setAttribute("class", "img-zoom-lens");
/*insert lens:*/
img.parentElement.insertBefore(lens, img);
/*calculate the ratio between result DIV and lens:*/
cx = result.offsetWidth / lens.offsetWidth;
cy = result.offsetHeight / lens.offsetHeight;
/*set background properties for the result DIV:*/
result.style.backgroundImage = "url('" + img.src + "')";
result.style.backgroundSize = (img.width * cx) + "px " + (img.height * cy) + "px";
/*execute a function when someone moves the cursor over the image, or the lens:*/
lens.addEventListener("mousemove", moveLens);
img.addEventListener("mousemove", moveLens);
/*and also for touch screens:*/
lens.addEventListener("touchmove", moveLens);
img.addEventListener("touchmove", moveLens);