Remove the leading slash with /ckeditor/ckeditor.js (try using ckeditor/ckeditor.js ).
A leading slash means root .
So if you use a URL like http://bp.php5.cz/ and then say /ckeditor/ckeditor.js , that would mean http://bp.php5.cz/ckeditor/ckeditor.js . But if your url is localhost/xampp/ , it will solve localhost/ckeditor/ckeditor.js , which is not what you want.
If you omit the leading slash, the relative URL will be resolved from the "current URL", so in both cases it will be correct.
The safest way is, of course, to use an absolute URL.
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