JSFiddle - React, Tailwind, and code Playground

HTML

<div id="my-div"></div>

CSS

#my-div{
    display: none;
    position: absolute;
    left: -160px;
    bottom: -150px;
}

JavaScript

function getCssProperty(elmId, property){
   var elem = document.getElementById(elmId);
   return window.getComputedStyle(elem,null).getPropertyValue(property);
}
// You could now get your value like
alert(getCssProperty("my-div", "left"));