Gets the first column in a specified range of cells within a sheet that identifies the starting boundary of a cell range along the horizontal axis of a spreadsheet.
Object.defineProperty(CellRange.prototype, 'firstColumn',
get: function()
)
The index of the first column in the cell range.
The FirstColumn property returns the index of the first column in a specified range of cells. This index is zero-based, meaning the first column in the spreadsheet is represented as 0.