javascript.options.strict

JavaScript warnings are generated when code is executed that doesn't cause a run-time error, but is non-standard, poorly written, or prone to cause logic errors. This preference controls whether JavaScript warnings are logged to the JavaScript Console.

Possible values and their effects:

True: Show JavaScript errors and warnings.

False: Show JavaScript errors only. (Default)

See also: http://kb.mozillazine.org/Javascript.options.strict