javascript/TraceLevel is a SAP Parameter attribute which is used to control CL_JAVA_SCRIPT: switch on/off trace files, "0" no "50" max. trace information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
You can use this parameter to activate/deactivate a trace for the
integrated JavaScript Machine (CL_JAVA_SCRIPT). The value 0 means no
log. Otherwise, the higher the value, the more detailed the content of
the trace file. The trace is only meant for remote support and is
therefore normally deactivated. When problems arise, a trace level of 5
is recommended for an ongoing analysis, or 10 for a detailed analysis.
CAUTION
Activating the trace leads to significant reduction in runtime
performance for all JavaScript applications!
See SAP Parameter Documentation for full SAP documentation for this profile parameter.