CODE EXAMPLE FOR JAVASCRIPT

getComputedStyle

let box = document.querySelector('.box');
let style = getComputedStyle(box);

let borderTopWidth = parseInt(style.borderTopWidth) || 0;
let borderLeftWidth = parseInt(style.borderLeftWidth) || 0;
let borderBottomWidth = parseInt(style.borderBottomWidth) || 0;
let borderRightWidth = parseInt(style.borderRightWidth) || 0;
Code language: JavaScript (javascript)