check class from left position by window js code example

Example 1: javascript get div x y position

window.scrollY + document.querySelector('#elementId').getBoundingClientRect().top // Y

window.scrollX + document.querySelector('#elementId').getBoundingClientRect().left // X

Example 2: js get element by X Y

// get the element at a certain (x, y) position
var element = document.elementFromPoint(x, y);

// for a list of elements
var elements = document.elementsFromPoint(x, y);

.