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.
  • 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


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

Browser compatibility

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

[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.

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

See also

Document Tags and Contributors

Last updated by: Sebastianz,
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