Several PHP functions that are coherent with special character processing

Several PHP functions related to special character handling

Name of function	Interpretation	Introduced
Htmlspecialchars	Combine with, single double quotes, greater than, and less than sign into HTML format	& Turn Into & "Turn into" ' Turn into ' <> > Turn into >
Htmlentities ()	All characters are converted to HTML format	In addition to the above Htmlspecialchars characters, the double-byte characters are displayed as encodings.
Addslashes	Single double quote, backslash, and null plus backslash escape	The characters that are changed include single quotation marks ('), double quotation marks ("), backslash backslash (\), and null character null.
Stripslashes	Remove backslash characters	Removes the backslash character from the string. If you have two consecutive backslashes, remove one and leave one. If there is only one backslash, remove it directly.
Quotemeta	Add Reference symbol	The string that contains the. \\ + * ? [ ^ ] ($) to precede the character with the backslash "\" symbol.
NL2BR ()	Converts a newline character to
Strip_tags	Remove HTML and PHP tags	Remove any HTML tags and PHP tags from the string, including the content between tags blocking. Note that if there is an error in the string HTML and PHP tags, an error will also be returned.
Mysql_real_escape_string	Escaping special characters in SQL strings	Escaped \x00 \ r \ n space \ ' "\x1a, which is useful for multibyte character processing. Mysql_real_escape_string will judge the character set, mysql_escape_string do not consider it.

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