说明： This method has the disadvantage that your batch file may "accidently" really use the label to jump to.
As Marc Stern points out in one of his MS-DOS batch files Tips & Tricks, this can be solved by using a double colon ( :: ) as the first characters of the comment line.
That way, the label is invalid but still treated as a label, and skipped (i.e. the next line is read immediately by COMMAND.COM, without the need to reopen the batch file). This may speed up reading large blocks of comment lines from slow (floppy) drives.