Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

Note: In Selectors Level 4, the :empty selector was changed to act like :-moz-only-whitespace, but no browser currently supports this yet.

The :-moz-only-whitespace CSS pseudo-class matches elements that only contain text nodes that only contain whitespace. (This includes elements with empty text nodes and elements with no child nodes.)


:-moz-only-whitespace {
  /* ... */


Simple :-moz-only-whitespace example


<div> </div>


div {
  border: 4px solid red;

:-moz-only-whitespace {
  border-color: lime;



Briefly defined as :blank in Selectors Level 4, but then the functionality was merged into :empty and :blank redefined to mean empty <input>.

Browser compatibility

BCD tables only load in the browser

See also