Javascript Chinese character byte judgment_form special effects

Copy code The code is as follows:

function checkstr(str) {
num=str.length
var arr=str.match(/[^\\\\\\\\x00-\\\\\\\\x80]/ig)
if(arr!=null)num =arr.length
return num
}

function CheckUserName(UserName) {
if(checkstr(UserName) > 30 || checkstr(UserName) < 4) {

} else {

}
}

Javascript’s length() considers a Chinese character or a letter to be 1 byte. This function can determine whether a Chinese character is 2 characters. Festival.