你需要从PHP中获取有用错误的两行关键代码是:

ini_set('display_errors',1);
 error_reporting(E_ALL);

正如其他贡献者所指出的那样，出于安全原因，这些功能在默认情况下是关闭的。作为一个有用的技巧——当你设置你的网站时，为你的不同环境做一个切换是很方便的，这样在你的本地和开发环境中，这些错误默认是打开的。这可以通过以下代码实现(理想情况下是在index.php或配置文件中，这样从一开始就处于活动状态):

switch($_SERVER['SERVER_NAME'])
{
    // local
    case 'yourdomain.dev':
    // dev
    case 'dev.yourdomain.com':
        ini_set('display_errors',1);
        error_reporting(E_ALL);
    break;
    //live
    case 'yourdomain.com':
        //...
    break;
}

打开错误报告是正确的解决方案，但是它似乎不会在打开它的程序中生效，而只会在随后包含的程序中生效。

因此，我总是创建一个文件/程序(我通常称之为“genwrap.php”)，它的代码本质上与这里流行的解决方案相同。打开错误报告)，然后它还包括我实际想要调用的页面。

实现这个调试有两个步骤;

首先，创建genwrap.php，然后把下面的代码放进去:

<?php
error_reporting(-1);
ini_set('display_errors', 'On');

include($_REQUEST['page']);
?>

第二，将你想要调试的程序/页面的链接改为通过genwrap.php，

例如:改变:

$.ajax('dir/pgm.php?param=val').done(function(data) { /* ... */

to

$.ajax('dir/genwrap.php?page=pgm.php&param=val').done(function(data) { /* ... */

使用@inexistent_function_call ();将导致解释器安静地停止并中止脚本解析。您应该检查无效的函数，并尽量不要使用错误抑制操作符(@ char)

除了这里所有精彩的答案，我还想特别提一下MySQLi和PDO库。

为了……

总是看到数据库相关的错误，和 避免检查方法的返回类型以查看是否出现了错误

最好的选择是将库配置为抛出异常。

MySQLi

将此添加到脚本顶部附近

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

最好放在使用新的mysqli()或mysqli_connect()之前。

PDO

在连接实例上将PDO::ATTR_ERRMODE属性设置为PDO::ERRMODE_EXCEPTION。你可以在构造函数中这样做

$pdo = new PDO('driver:host=localhost;...', 'username', 'password', [
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
]);

或者在创造之后

$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

这个答案是由冗余部门为您带来的。

ini_set() / php.ini / .htaccess / .user.ini The settings display_errors and error_reporting have been covered sufficiently now. But just to recap when to use which option: ini_set() and error_reporting() apply for runtime errors only. php.ini should primarily be edited for development setups. (Webserver and CLI version often have different php.ini's) .htaccess flags only work for dated setups (Find a new hoster! Well managed servers are cheaper.) .user.ini are partial php.ini's for modern setups (FCGI/FPM) And as crude alternative for runtime errors you can often use: set_error_handler("var_dump"); // ignores error_reporting and `@` suppression error_get_last() Can be used to retrieve the last runtime notice/warning/error, when error_display is disabled. $php_errormsg Is a superlocal variable, which also contains the last PHP runtime message. isset() begone! I know this will displease a lot of folks, but isset and empty should not be used by newcomers. You can add the notice suppression after you verified your code is working. But never before. A lot of the "something doesn't work" questions we get lately are the result of typos like: if(isset($_POST['sumbit'])) # ↑↑ You won't get any useful notices if your code is littered with isset/empty/array_keys_exists. It's sometimes more sensible to use @, so notices and warnings go to the logs at least. assert_options(ASSERT_ACTIVE|ASSERT_WARNING); To get warnings for assert() sections. (Pretty uncommon, but more proficient code might contain some.) PHP7 requires zend.assertions=1 in the php.ini as well. declare(strict_types=1); Bending PHP into a strictly typed language is not going to fix a whole lot of logic errors, but it's definitely an option for debugging purposes. PDO / MySQLi And @Phil already mentioned PDO/MySQLi error reporting options. Similar options exist for other database APIs of course. json_last_error() + json_last_error_msg For JSON parsing. preg_last_error() For regexen. CURLOPT_VERBOSE To debug curl requests, you need CURLOPT_VERBOSE at the very least. shell/exec() Likewise will shell command execution not yield errors on its own. You always need 2>&1 and peek at the $errno.

error_reporting(E_ALL | E_STRICT);

并在php.ini中打开显示错误