The IDE/Debugger can help the WebMaster develop and solve problems live as they occur on the server, with full support for editing, watchpoint, breakponts, variable settings, etc... The following screen-capture image shows the debugger running on the 2*3+4 script problem.

From the debugger it is easy to see that num3 wrongly retrieved the value from gInputField2. At this point you could change the variable name to gInputField3, save the file, and you are finished; the script is fixed!