I downloaded the onchange plug-in (https://ckeditor.com/cke4/addon/onchange). Connect it in config.js:
config.extraPlugins = 'onchange';
I wrote the following code in config.js:
CKEDITOR.on('instanceReady', function (ev) {
var editor = ev.editor;
editor.on('change', function() {
console.log('zzz');
});
});
And now when I write something in my editor, zzz is output twice. Why is that? Should be output once.
I deleted the line:
config.extraPlugins = 'onchange';
And everything began to work as it should.