Question about unicode encoding

Ask a unicode encoding question. js has a function String. charCodeAt that converts a character at the specified position of a String to unicode encoding and returns a number. Now I want to convert a website such as http://bbs.csdn.net/into a unicodecharacter string. I want to use the PHP letter to ask a question about unicode encoding.
The String. charCodeAt function in js can convert characters at the specified position of a String to unicode encoding and return a number. Now I want to set a URL, such as ingress? After searching for Chinese characters on the Internet for a long time, I found that they are converted to unicode encoding. All I want is to convert English letters and symbols! Share:
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For basic ASCII characters only, you only need to use the ord function.
If it contains Chinese characters, iconv function transcoding is available, the target character set is UCS-2
However, it should be noted that in the UCS-2 character set, the basic ASCII character is also 2 bytes