check if update web page

i downloaded a web page ".html" on mu hard disk i would like to check if this page has been updated recently without downloading the page again.. P.S. when i use last-modi开发者_运维问答fied it doesn't work on some servers Can anyone help me?? thanks in advance

If last-modified doesnt work you cant really check. However you can fudge it by checking the content length if the content length is always the same unless updated. I assume you already know you can use the HEAD method to check a page without getting the content.