The length of the string received by ajax is different.

The length of the string received by ajax is not the same. I use ajax to pass a parameter, and then php receives it and prints it with var_dump. the length is 41. then I copy the same string to php, print the var_dump directly. the length is 42. as follows: string (41) & quot; & lt; pclass = & quot; xg1 & quot; & g ajax receives different string lengths
I used ajax to pass a parameter, and php received it, and printed it with var_dump. the length is 41. then I copied the same string to php and printed it with var_dump. the length is 42. as follows:

String (41 )"
[Data]"
String (42 )"
[Data]"

The string is the same and the length is different. I don't know why the difference may occur. considering that the encoding may be different, I tried
Declare the encoding when receiving the message, as shown in figure
Header ("Content-type: text/html; charset = GB2312 ");
The problem is not solved if the string is converted into the same encoding.
What is the most likely cause of this situation?

------ Solution --------------------
This is a difference caused by the operating system.
In the window system, press enter to wrap the line (\ r \ n)
Linux is a line feed (\ n)

Exactly one character difference
------ Solution --------------------
Print_r (unpack ('H * ', $ str ));
Let's take a look!
What is the use of a guess?