CYJS framework provides a live page edit mode.
By clicking these icons on the sidemenu right, CYJS will automatically load the 3 HTML/JS/CSS files for the corresponding page. You are free to edit them then to save them if you have decided to authorize this by updating php/uploadfile.php.
Please again : take care, it would be easy for an unidentified hacker to alter your installation if you have modified the php/uploadfile.php to accept file writing without any authentication. No risk if you did not change it.