For HTML pages, or for dynamic pages that change only infrequently, we suggest this type of monitoring. We report to you when a page changes length. Each length is remembered and you’re only alerted once for each new length.

This filter is particularly appropriate for javascript (JS) files, which are not supposed to change length. These files are likely targets for the injection of malware.

For pages than change length frequently, we suggest you try a different method.

If you’re happy with a fixed-content scan, you probably don’t need any of the more sophisticated scans at all, because they don’t provide any additional safety.