dedecms dream weaving tag tag does not support capital letters fix

Inadvertently found that some of the tag tags in my dedecms blog were invalid. At first I thought my tags were wrong, but I didn't understand it for a long time, and then I accidentally discovered that it was because the dedecms 5.7 version tag tags did not support capitalizationLetter, the following is the solution: open the tags.php file in the root directory of the website,
put the following line of code

$tag = trim($_SERVER['QUERY_STRING']); 

Change to

$tag = strtolower(trim($_SERVER['QUERY_STRING']));

Note: PHP strtolower() function
Definition and usage
The strtolower() function converts a string to lowercase.
Syntax strtolower(string)
Parameter Description
string Required.Specifies the string to convert.
Example
Output:
hello world!