HTMLTableCellElement - Web APIs
htmltablecellelement.choff a domstring containing a integer indicating how many characters must be left at the right (for left-to-right scripts; or at the left for right-to-left scripts) of the character defined by htmltablecellelement.ch.
... recommendation the following properties have been obsoleted: align, axis, bgcolor, height, width, ch, choff, nowrap, and valign.

HTMLTableColElement - Web APIs
htmltablecolelement.choff is a domstring representing the offset for the alignment character.

HTMLTableRowElement - Web APIs
htmltablerowelement.choff is a domstring containing a integer indicating how many characters must be left at the right (for left-to-right scripts; or at the left for right-to-left scripts) of the character defined by htmltablerowelement.ch.

HTMLTableSectionElement - Web APIs
htmltablesectionelement.choff is a domstring containing a integer indicating how many characters must be left at the right (for left-to-right scripts; or at the left for right-to-left scripts) of the character defined by htmltablerowelement.ch.