Check out example codes for "div element position in screen". It will help you in understanding the concepts better.

Code Example 1

function offset(el) {    var rect = el.getBoundingClientRect(),    scrollLeft = window.pageXOffset || document.documentElement.scrollLeft,    scrollTop = window.pageYOffset || document.documentElement.scrollTop;    return { top: rect.top + scrollTop, left: rect.left + scrollLeft }}
// example usevar div = document.querySelector('div');var divOffset = offset(div);console.log(divOffset.left, divOffset.top);

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