int length

Source 

@DomName('HTMLSelectElement.length')
@DocsEditable()
int get length => _blink.BlinkHTMLSelectElement.instance.length_Getter_(this);
void length=(int value)

Source 

@DomName('HTMLSelectElement.length')
@DocsEditable()
set length(int value) =>
    _blink.BlinkHTMLSelectElement.instance.length_Setter_(this, value);