


1) Use the tag to set the page encoding
The function of this tag is to declare what character set encoding the client's browser uses to display the page. xxx can be GB2312, GBK, UTF-8 (and MySQL is different, MySQL is UTF8) and so on. Therefore, most pages can use this method to tell the browser what encoding to use when displaying this page, so as to avoid encoding errors and garbled characters. But sometimes we will find that this sentence still doesn't work. No matter which xxx is, the browser always uses the same encoding. I will talk about this later.
Please note that it belongs to HTML information and is just a statement, which only indicates that the server has passed the HTML information to the browser.
2) header("content-type:text/html; charset=xxx");
The function of this function header() is to convert the information in the brackets Sent to http headers. If the content in the brackets is as mentioned in the article, the function is basically the same as the label. If you compare the first one, you will find that the characters are similar. But the difference is that if there is this function, the browser will always use the xxx encoding you requested and will never be disobedient, so this function is very useful. Why is this happening? Then we have to talk about the difference between http headers and HTML information:
http header is a string sent by the server before sending HTML information to the browser using the http protocol. The tag belongs to HTML information, so the content sent by header() reaches the browser first. The popular point is that header() has a higher priority (I don’t know if I can say this). If a php page has both header("content-type:text/html;charset=xxx") and header("content-type:text/html;charset=xxx"), the browser will only recognize the former http header and not the meta. Of course, this function can only be used within php pages.
There is also a question left, why does the former definitely work, but the latter sometimes does not work? This is the reason why we want to talk about Apache next.
3) AddDefaultCharset
In the conf folder in the Apache root directory, there is the entire Apache configuration document httpd.conf.
Open httpd.conf with a text editor. Line 708 (different versions may be different) contains AddDefaultCharset xxx, where xxx is the encoding name. The meaning of this line of code: Set the character set in the http header of the web page file in the entire server to your default xxx character set. Having this line is equivalent to adding a line of header("content-type:text/html; charset=xxx") to each file. Now you can understand why the browser always uses gb2312 even though it is set to utf-8.
If there is header("content-type:text/html; charset=xxx") in the web page, the default character set will be changed to the character set you set, so this function will always be useful. If you add a "#" in front of AddDefaultCharset xxx, comment out this sentence, and the page does not contain header ("content-type..."), then it is the meta tag's turn to take effect.
The above priority is listed below:
.. header("content-type:text/html; charset=xxx")
.. AddDefaultCharset xxx
..
If you are a web programmer, it is recommended to add a header ("content-type: text/html; charset=xxx") to each of your pages, so that you can ensure It can be displayed correctly on any server and has strong portability.
4) default_charset configuration in php.ini:
default_charset = "gb2312" in php.ini defines the default language character set of php. It is generally recommended to comment out this line and let the browser automatically select the language based on the charset in the web page header instead of making a mandatory requirement. This way, web services in multiple languages can be provided on the same server.
Solution to the problem of garbled Chinese characters intercepted by PHP Application of mb_substr function
A collection of mysql Chinese garbled code solutions

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。


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