JavaScript function that returns the cell of the table by given coordinates considering colSpan and rowSpan of the cells.

getTableCell.js

/**
 * Returns the cell of the table by given (x;y) coordinates considering colSpan and rowSpan of the cells.
 * @param {HTMLElement} table - HTML table
 * @param {number} x - X position in table matrix
 * @param {number} y - Y position in table matrix
 * @returns {HTMLElement|null}
 */
var getTableCell = function (table, x, y) {
    var m = [], row, cell, xx, tx, ty, xxx, yyy;
    for(yyy = 0; yyy < table.rows.length; yyy++) {
        row = table.rows[yyy];
        for(xxx = 0; xxx < row.cells.length; xxx++) {
            cell = row.cells[xxx];
            xx = xxx;
            for(; m[yyy] && m[yyy][xx]; ++xx) {}
            for(tx = xx; tx < xx + cell.colSpan; ++tx) {
                for(ty = yyy; ty < yyy + cell.rowSpan; ++ty) {
                    if (!m[ty])
                        m[ty] = [];
                    m[ty][tx] = true;
                }
            }
            if (xx <= x && x < xx + cell.colSpan && yyy <= y && y < yyy + cell.rowSpan)
                return cell;
        }
    }
    return null;
};