I'm assuming you are referring to using those letters for folders in your project or for project names? Restrictions on those elements are standard Cordova restrictions, trying to use them may result in problems with PhoneGap Build or Cordova CLI. Using those letters within your application should not be an issue, but using them to name files, folders and projects can cause problems.
Thanks for the answer... No it's not for a project name, a folder name or a file name, it's only in an normal HTML text, for instance in a <p> ......</p> paragraph.
In the XDK Develop, as these letters are not on my keyboard, I don't know how to write them.... The standard method, typing the Alt+128 or (135), Extended ASCII Character, does not work in the XDK Editor. Develop screen..
I do not use Cordova... I am just writing my first web page (in French).. Thanks for help!
Pollkua -- the XDK is not a good tool for creating web pages. For that I would use the Brackets editor directly, which you can download here > http://brackets.io/ < it's the same editor that's in the XDK, but more recent and includes the ability to show your pages in a browser, directly.
Thanks for the advice, I will try Brackets.
I used XDK because I enrolled in the W3Cx course (HTML5 and CSS Fundamentals) and they use and recommand (among others) XDK for the exercises.. Thanks again!!