Why doesn’t text-overfilow show the omission mark?

The text-overflow attribute is only to indicate whether to display the omission mark when the text overflows, and does not have other style attribute definitions. To achieve the effect of ellipsis when overflowing, it needs to be defined, that is, to force the text to be displayed in one line (white-space: nowrap;) and the overflow content to be hidden (overflow: hidden;). Only in this way can the overflow text display the ellipsis effect.