mysql escape function javascript

MySQL and JavaScript are commonly used databases and programming languages. They often need to convert data to each other in applications. For special characters or reserved words in MySQL, escape functions need to be used in JavaScript to ensure the correctness of the data. This article will introduce in detail the escaping of special characters in MySQL and the corresponding escape functions in JavaScript.

Escape of special characters in MySQL

Special characters in MySQL include single quotes, double quotes, backslashes, tabs, carriage returns, line feeds, etc. These special characters It has a special meaning in MySQL. If used directly in a SQL statement, it will cause syntax errors or SQL injection. Therefore, when using MySQL for data operations, these special characters need to be escaped first to avoid problems. MySQL provides a special character escape function: mysql_real_escape_string(), which can escape special characters into ordinary characters in MySQL.

The mysql_real_escape_string() function receives a string to be escaped as a parameter and returns the escaped string. For example, for a string containing single quotes, you can use the following code to escape:

$str = "It's a rainy day";
$str_escaped = mysql_real_escape_string($str);

In the above code, the value of $str_escaped is "It's a rainy day", where the single quotes are escaped into strings "'".

In addition to mysql_real_escape_string(), MySQL has another escape function: addslashes(). This function can also escape special characters into ordinary characters, but its escaping method is not exactly the same as mysql_real_escape_string(). Therefore, you need to pay attention to the difference when using it.

Escape functions in JavaScript

For strings escaped in MySQL, they need to be processed through the corresponding escape functions in JavaScript to avoid syntax errors caused by special characters. JavaScript provides multiple escape functions, including: encodeURI(), encodeURIComponent(), escape(), etc. When dealing with MySQL escaped strings, the encodeURIComponent() function should be used.

The encodeURIComponent() function receives a string as a parameter and returns the URI encoding of the string, which conforms to the URI specification and encodes all non-alphanumeric characters, including reserved words and special characters. For example, for the escaped MySQL string 'It's a rainy day', you can use the following code to process:

var str = 'It\'s a rainy day';
var str_encoded = encodeURIComponent(str);

In the above code, the value of str_encoded is "It\'s a rainy day", where all The special characters are escaped into URI encoding.

When you need to convert the URI encoding into the original string, you can use the decodeURIComponent() function to decode, for example:

var str_decoded = decodeURIComponent(str_encoded);

In the above code, the value of str_decoded is "It's a rainy day" , that is, the string before escaping.

Summary

Special characters and reserved words in MySQL need to be escaped to be used correctly in SQL statements. In JavaScript, MySQL escaped strings need to be processed to avoid syntax. mistake. When using it, you should choose the appropriate escape function according to the specific situation, and pay attention to the difference before and after escape. By correctly handling special character escapes, data accuracy and application stability can be guaranteed.

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