php output page error

Recently, have you encountered an output page error when developing a website using PHP? This is a very common problem. There are usually three situations when outputting page errors in PHP: syntax errors, runtime errors and logic errors. In this article, we will explain these three situations and their solutions in detail to help you quickly solve the problem of output page errors.

1. Grammar Error

Grammar error is one of the most common types of errors. When there is a syntax error in the PHP code, the page will often display a fatal error, indicating the specific error location and error message, as shown below:

Parse error: syntax error, unexpected '{' in /path/ to/file.php on line 11

This error will clearly tell you where the syntax error occurs. If this error occurs, you need to carefully check the relevant line of code and nearby lines of code to find and solve it. mistake.

For example, if you find an unexpected brace in the code line 11 pointed to in the above error message, you need to check the code segment before the brace to see if the closing tag is missing.

The way to solve syntax errors is to keep editing the code to ensure that all opening and closing tags have been written, and to master the syntax rules commonly used in PHP programming.

2. Run-time errors

Run-time errors are often inconsistent with code syntax and can be caused by many factors. Runtime errors typically display a warning or error message of a specified type on the page. Under normal circumstances, these errors will be displayed at the end of the page. The specific information may include:

Warning: Division by zero in /path/to/file.php on line 20

as shown above , a type of error like dividing by zero may occur, and you need to naturally find that line of code and revise it.

The method to solve the runtime error can be:

1. Avoid dividing by zero in the code, and make sure to judge the valid data before operating the data.
2. Make sure the code is compatible with the PHP version. Some features in PHP may be outdated or not supported in older versions, causing runtime errors if your code is supported in newer versions of PHP but not in older versions.
3. Logical Error

Logical errors are the most difficult of the three error types to find and debug. Logic errors usually do not directly prompt an error, but cause the output result to be different from the expected result. For example, you might write a calculator program, but the output is not the correct calculation. This situation is usually caused by logic problems in the program or function.

To resolve logic errors, you need to check the logic in your code very carefully. You should know what your programs and functions are supposed to do, and keep the logic as simple as possible. If you encounter a logic error, you can start by debugging and optimizing the program to find the faulty code and make adjustments.

Debugging Tools

Whether it is a syntax error, a runtime error, or a logic error, debugging tools are indispensable tools for you. Let's introduce several debugging tools that are currently commonly used in PHP.

1. PHPstorm

PHPstorm is a good PHP IDE that provides many functions for checking PHP code. It integrates PHPUnit and has built-in Xdebug, so it can be easily Conveniently conduct unit testing and debugging to help you pinpoint error locations.

2. XDebug

, by single-step debugging the program to see how the code executes and where problems occur.

3. FirePHP

FirePHP is a PHP application development program based on the Firefox monitor. It can be debugged very conveniently. It can send debugging information to the browser. in the console rather than directly outputting it on the page.

Conclusion

When developing a PHP website, output page errors are inevitable. However, if you know how to identify and resolve syntax errors, runtime errors, and logic errors, you can locate and fix errors faster and improve development efficiency. In addition, using more debugging tools is also very beneficial. While fixing bugs may take some time, it is important to improve code quality and user experience.

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