新写的url验证

var reg = /^((http|https|ftp)\:\/\/)?(((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])\.){3}(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])|([^0-9][a-zA-Z_0-9\-\.\/])+)((:[a-zA-Z0-9]*)?\/?[a-zA-Z0-9\-\._\?\,\/\:\'\/\\\+&%\$#\=~])*$/;