colgroup elementtable element, after any caption elements and before any thead, tbody, tfoot, and tr elements.span attribute is present: Empty.span attribute is absent: Zero or more col elements.span
interface HTMLTableColElement : HTMLElement {
attribute unsigned long span;
};
The colgroup element represents a group of one or more columns in the table that is its parent, if it has a parent and that is a table element.
If the colgroup element contains no col elements, then the element may have a span content attribute specified, whose value must be a valid non-negative integer greater than zero.
The span IDL attribute must reflect the content attribute of the same name. The value must be limited to only non-negative numbers greater than zero.