Modify an AEM OOB script

Hi there,

I would like to know what is the best way to modify an OOB functionality in AEM.

The initial request is to restrict some characters when adding Assets to DAM. I see that in fileupload.js there is a Ilegal-characters variable that contains some of them.

I would like to know what is the best way to recreate this functionality and create a custom function to validate characters.

Regards.