Hey Ahmed,
I understand that you are facing an error while opening any type of file in MATLAB Online.
According to Stack Overflow, the error is a JavaScript error, which is a browser error. For that reason, please try clearing the browser cache.
Also try opening your file with 'open' function. For more information on the 'open' function you can refer Mathworks Documentation - https://in.mathworks.com/help/matlab/ref/open.html
I hope this help!
