How to validate a filename to check/allow English chars only, no Chinese chars

My code is here and its not working, still allow upload a file with Chinese filename.

isValidFilenamechar (file) {
var re = /^[A-Za-z0-9 -_()]+$/;
var isValid = re.test(file.name.value)
if (!isValid) {
return false
}
return true
},