如果在执行php程序时看到这条警告:"Warning: Cannot modify header information - headers already sent by ...."Few notes based on the following user posts:有以下几种解决方法:1. Blank lines (空白行):Make sure no blank line after <?php ... ?> of the calling php scrīpt.检查有<?php ... ?> 后面没有空白行，特别是include或者require的文件。不少问题是这些空白行导致的。2. Use exit statement (用exit来解决):Use exit after header statement seems to help some people在header后加上exit();header ("Location: xxx");exit();3. PHP has t...