php coding_PHP tutorial

1. Page encoding
1. Use the tag to set the page encoding
The purpose 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 (different from MySQL, which is UTF8), etc. 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 belongs to HTML information and is just a statement. It works to indicate that the server has passed HTML information to the browser.
2. header("content-type:text/html; charset=xxx");
The function of this function header() is to send the information in the brackets to the http header.
If the content in the brackets is as mentioned in the article, the function is basically the same as the tag. If you compare it with 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 HTTPS headers and HTML information:
The https header is a string sent by the server before sending HTML information to the browser using the HTTP protocol.
Because the meta tag belongs to html information, the content sent by header() reaches the browser first. The popular point is that header() has a higher priority than meta (I don’t know if I can say this). Add a php page that has both header("content-type:text/html; charset=xxx") and , 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 doesn't? This is 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 (may be different in different versions) contains AddDefaultCharset xxx, where xxx is the encoding name. The meaning of this line of code: Set the character set in the https header of the web page file in the entire server to your default xxx character set. Having this line is equivalent to adding a header ("content-type: text/html; charset=xxx") to each file. Now you can understand why the browser always uses gb2312 even though the meta setting is utf-8.
If there is a 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.
Summary:
Let’s sort
header("content-type:text/html; charset=xxx")
　AddDefaultCharset xxx　

If you are a web programmer, add a header ("content-type: text/html; charset=xxx") to each of your pages to ensure that it can be displayed correctly on any server and is highly portable.
As for the sentence AddDefaultCharset xxx, whether it should be commented or not is a matter of opinion. Anyway, I commented it out, but I also need to write header() when writing a page, so that it can be displayed normally on the server.
2. Database encoding
Before querying the database, the PHP program first executes mysql_query("SET NAMES xxxx"); where xxxx is the encoding of your web page (charset=xxxx). If charset=utf8 in the web page, then xxxx=utf8, if charset=gb2312 in the web page, Then xxxx=gb2312, almost all WEB programs have a common code to connect to the database, which is placed in a file. In this file, just add mysql_query ("set names").
SET NAMES displays what character set is used in the SQL statement sent by the client. Therefore, the SET NAMES 'utf-8' statement tells the server that "future information from this client will use the character set utf-8." It also specifies the character set for the results that the server sends back to the client. (For example, if you use a SELECT statement, it indicates what character set is used for the column values.)

Author "Dancer Blog"

http://www.bkjia.com/PHPjc/478632.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/478632.htmlTechArticle1. Page encoding 1. Use META http-equiv=content-type content=text/html; charset=xxx Tag Settings Page Encoding The purpose of this tag is to declare what character set the client's browser uses...