Question

php网页报很多notice的错误

这是被人发给我的系统，但是打开报很多错，我想知道这些错误是什么原因造成的？
除了修改php.ini和添加error_reporting (E_ALL & ~E_NOTICE);外，有没有其他解决办法。
PHP Notice: A session had already been started - ignoring session_start() in E:\wwwroot\shang\top.php on line 2 PHP Notice: Use of undefined constant username - assumed 'username' in E:\wwwroot\shang\top.php on line 48 PHP Notice: Use of undefined constant username - assumed 'username' in E:\wwwroot\shang\top.php on line 55 PHP Notice: Use of undefined constant id - assumed 'id' in E:\wwwroot\shang\left.php on line 121 PHP Notice: Use of undefined constant title - assumed 'title' in E:\wwwroot\shang\left.php on line 123 PHP Notice: Use of undefined constant title - assumed 'title' in E:\wwwroot\shang\left.php on line 124 PHP Notice: Use of undefined constant id - assumed 'id' in E:\wwwroot\shang\left.php on line 121 PHP Notice: Use of undefined constant title - assumed 'title' in E:\wwwroot\shang\left.php on line 123 PHP Notice: Use of undefined constant title - assumed 'title' in E:\wwwroot\shang\left.php on line 124 PHP Notice: Use of undefined constant id - assumed 'id' in E:\wwwroot\shang\left.php on line 121 PHP Notice: Use of undefined constant title - assumed 'title' in E:\wwwroot\shang\left.php on line 123 PHP Notice: Use of undefined constant title - assumed 'title' in E:\wwwroot\shang\left.php on line 124 PHP Notice: Use of undefined constant id - assumed 'id' in E:\wwwroot\shang\left.php on line 121 PHP Notice: Use of undefined constant title - assumed 'title' in E:\wwwroot\shang\left.php on line 123 PHP Notice: Use of undefined constant title - assumed 'title' in E:\wwwroot\shang\left.php on line 124 PHP Notice: Use of undefined constant linkurl - assumed 'linkurl' in E:\wwwroot\shang\left.php on line 174 PHP Notice: Use of undefined constant linkname - assumed 'linkname' in E:\wwwroot\shang\left.php on line 176 PHP Notice: Use of undefined constant linkname - assumed 'linkname' in E:\wwwroot\shang\left.php on line 177 PHP Notice: Use of undefined constant linkurl - assumed 'linkurl' in E:\wwwroot\shang\left.php on line 174 PHP Notice: Use of undefined constant linkname - assumed 'linkname' in E:\wwwroot\shang\left.php on line 176 PHP Notice: Use of undefined constant linkname - assumed 'linkname' in E:\wwwroot\shang\left.php on line 177 PHP Notice: Use of undefined constant linkurl - assumed 'linkurl' in E:\wwwroot\shang\left.php on line 174 PHP Notice: Use of undefined constant linkname - assumed 'linkname' in E:\wwwroot\shang\left.php on line 176 PHP

Answer 1

这个是正常的，因为php是动态语言，所以可以在任何地方随便添加变量而不需要声明。这只是编译器提醒你有些页面中有某些未定义的变量而已，因为未声明而使用的变量是很容易出现错误的。如果你要真正消除这个问题，你就应该养成良好的变成习惯，在变量的使用前先声明变量!

Answer 2

根据log信息去查找啊，都说了line 176 ，就去看那行的代码啊，你这有好多未定义的错误啊，应该是定义变量时出的问题，输入错误什么的