Reports whether or not the specified editor query command is supported by the browser.


isSupported = document.queryCommandSupported(command);


The command for which to determine support.

Return value

Returns a Boolean which is true if the command is supported and false if the command isn't.


  • If the command has no value or is disabled, an empty string is returned.
  • The 'fontSize' command is handled specially; if its value override is set, that gets converted to an integer number of pixels and returned as a legacy font size.
  • The 'paste' command return false not only if the feature is unavailable, but also if the script calling it has insufficient privileges to perform the action [1].
  • The 'cut' and 'copy' commands returns true only from user-initiated or privileged code [2].
  • If the command's value override is set, that gets returned.
  • Otherwise, the command's value is returned, as would be returned by document.queryCommandValue().


var flg = document.queryCommandSupported("SelectAll");

if(flg) {
  // ...Do something

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 17+ 9.0 (9.0) [1][2] 4.0 ? ?
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? 9.0 (9.0)[1][2] ? ? ?

[1] Before Firefox 41, for the command 'paste' Firefox incorrectly returned true when the paste feature was available but the calling script had insufficient privileges to actually perform the action.

[2] In Firefox, before Firefox 41, this was returning false. Now it returns true in user-initiated or privileged code.


Specification Status Comment
HTML Editing APIs
The definition of 'querycommandsupported' in that specification.
Editor's Draft  

See also

Document Tags and Contributors

Last updated by: Dan-Dascalescu,
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