源代码:
<HTML> <HEAD></HEAD> <FONT FACE="'Courier New',Verdana, Arial, Helvetica" SIZE=2> <!DOCTYPE html> <html> <body> <FONT COLOR=#ff0000><?php $str = chr(43); $str2 = chr(61); echo("2 $str 2 $str2 4"); ?></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>2 + 2 = 4</FONT> </body> </html> </HTML>