JSFiddle - React, Tailwind, and code Playground

HTML

<div id="image_1">hello</div>

CSS

#image_1 {
   position: absolute;
  top: 3vw;   
}

JavaScript

var element = document.getElementById('image_1'),
    style = window.getComputedStyle(element),
    top = style.getPropertyValue('top');

alert(top);