源代码:
<HTML> <HEAD></HEAD> <FONT FACE="'Courier New',Verdana, Arial, Helvetica" SIZE=2> <!DOCTYPE html> <html> <body> <FONT COLOR=#ff0000><?php echo(atanh(M_PI_4) . " "); echo(atanh(0.50) . " "); echo(atanh(-0.50) . " "); echo(atanh(1) . " "); echo(atanh(-1)); ?></FONT> </body> </html> </HTML>
运行结果：
<HTML> <HEAD></HEAD> <FONT FACE="'Courier New',Verdana, Arial, Helvetica" SIZE=2> <!DOCTYPE html> <html> <body> <FONT COLOR=#ff0000>1.0593061708232 0.54930614433405 -0.54930614433405 INF -INF</FONT> </body> </html> </HTML>