JSFiddle - React, Tailwind, and code Playground

HTML

<div id="quicklink" class="draggable">
    <img class="menu_icon" src="4a.png" src="" />                   
</div>

CSS

#quicklink {
    position: absolute;
    top: 500px;
    left: 500px;
}

JavaScript

var quicklink = document.getElementById('quicklink');
console.log(quicklink.style.top);

function getCssProperty(elmId, property){
   var elem = document.getElementById(elmId);
   return window.getComputedStyle(elem,null).getPropertyValue(property);
}
// You could now get your value like
var top = getCssProperty("quicklink", "top");
console.log(top)