In script console, after executing a broken script I have the following returned value
<response id="3" code="200"> {"output":"","stacktrace":"...... nts/ametys:' is not a valid path. 'X' not a valid name character....","error":""} </response>
where there is a broken char X that is xEFxBFxBF
that make the browser down with a very hidden returned message :
error on line 1 at column 42006: Char 0xFFFF out of allowed range