empty char range in regex

You will get this error with the following regex:
//var original = /[\x00-\x08\x0B\x0C\x0E-\x9F\uD800-\uDFFF\uFFFE\uFFFF]/;
var faultyRange = /[\x1F\x7F-\x84\x86]/;


var original2 = /^([\x00-\x7F]|[\xC2-\xDF][\x80-\xBF]|\xE0[\xA0-\xBF][\x80-\xBF]|[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}|\xED[\x80-\x9F][\x80-\xBF]|\xF0[\x90-\xBF][\x80-\xBF]{2}|[\xF1-\xF3][\x80-\xBF]{3}|\xF4[\x80-\x8F][\x80-\xBF]{2})*$/,