My first JAPH:
The following is legal, and produces output, in BASIC, Befunge, JavaScript (place between <SCRIPT> </SCRIPT> tags in an HTML file) and Perl.
'11';//;# 76+v,g4-\+0*55:<p0*73+5-*72p0*64*69p1*5 <
'';//;# japh >:1- JAPH \#^_$$"egnufeB">:#,_7>88*:6^
'0'?eval("function print(japh){document.write(japh"+
''+".replace(/Perl/,'JavaScript'))}",' '):$_=qq+0;
eval("print('Just Another Perl Hacker.')"),";\x22+;"
''/*";$\=$/; eval ;__END__
SUB eval (ja$,ph$)
PRINT MID$(ja$, 8, 13); "BASIC"; MID$(ja$, 25, 8)
END SUB ' Dedalus */