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How to avoid mulitple submission of form in html

by romy_mathew (Beadle)
on Sep 09, 2011 at 19:39 UTC ( #925155=perlquestion: print w/ replies, xml ) Need Help??
romy_mathew has asked for the wisdom of the Perl Monks concerning the following question:

I am creating a element like Face Book Like in a webpage and I want to disable the multiple submission of clicks on Like button.
I want like button to count only one click from the user and disable further clicks in the button or ignore the further clicks
now when ever i refresh the page and clicks on the like it get incremented... Please suggest a solution

Comment on How to avoid mulitple submission of form in html
Re: How to avoid mulitple submission of form in html
by ww (Bishop) on Sep 09, 2011 at 20:16 UTC
    Super Search for "cookies" for starters (and read the basic documentation about them)... other options that occur (OTTOMH) are even less attractive or much more complex.
Re: How to avoid mulitple submission of form in html
by Anonymous Monk on Sep 10, 2011 at 00:51 UTC

    Hi,

    Create an onclick trigger on your button which includes some javascript like -

    doc1.getElementById("testBut1").disabled=true;

    Should do the trick.

    J.C.

      Create an onclick trigger on your button which includes some javascript [...]] Should do the trick.

      Nope. Adding Javascript to the client will never solve a server side problem. Simply because Javascript is not always available on the client (LWP, WWW::Mechnanize, NoScript, filtering proxies, ...). And, quite obviously, it can be disabled on the client. In a WWW environment, you must not trust the client.

      The server has to detect that the form was submitted several times. The usual approach is to give each form a unique ID (e.g. a UUID) in a hidden field or as part of the submit URL; and to make sure that each and every ID is accepted exactly once.

      Alexander

      --
      Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)
Re: How to avoid mulitple submission of form in html
by DanielSpaniel (Scribe) on Sep 10, 2011 at 01:05 UTC

    The JavaScript idea will likely work reasonably well, but probably won't stop page refreshes, etc from causing the same problem. Then, of course, there are those users with JS turned off as well, and browsers that won't handle it.

    In fact, I don't think you probably really care if somebody clicks on it a hundred times - you just don't want the click to count. The way I've done stuff like this in the past is to simply create a database table, which logs the IP address and date/time of the click, and then just read the table before you add to whatever counter you're incrementing for your "like button," to make sure that the same IP hasn't clicked the button more than once in a given period.

    It's not completely perfect, because you could have multiple users with the same external IP (i.e. from a corporate office, for example). There's not much getting around that, without combining the idea with cookies. However, using this method together with cookies and the JavaScript idea, I would think is a fairly solid plan.

    Of course, if your users have user-names then it would be easy enough to just flag them in a database table as having "liked" whatever ... but then I don't suppose you'd be asking the question in the first instance if they had user-names.

      Excellent points, well said and ++ to DanielSpaniel.

      And (to the OP) just FTR, I offered "cookies" as an approach, knowing full well that some users will reject cookies; immediately remove them, or otherwise make their use ineffective. DanielSpaniel's points about the common IP's are well taken... and I should have offered some similar discussion of the limits of cookies, myself.

      Broadly though, unless the "like"-button-analogue is somehow related to operational control of a nuclear reactor ...or involved in handing out large sums in small, used, unmarked bills, you will reach a point where it's reasonable to say, 'I've done all that's within reason to secure X; now I need to decide if that's good enough, given the risks/exposures at stake.'

      I agree with the point Java script dont think will be helpful here but after reading about the session ID. I feel

      When a user visit a webpage a session id is created for that user, By keeping this session id as a hash session => 'true' at server.

      When the user click the Like button for the first time, the session key gets changed to session => 'false' .

      Now when the user refresh or click back button the session =>'fasle' remain same and thus further like count can be ignored.
        Thanks You all ...It Worked.....:)
Re: How to avoid mulitple submission of form in html
by Anonymous Monk on Sep 10, 2011 at 05:01 UTC
    If you do know the user-name, then you just need a "user-likes" table where "user-ID" and "topic-ID" are the primary key. Attempt to insert a row. If a matching row already exists, the insert will fail ... and you simply ignore it.
      Or generate a form-session-id, and when someone tries to submit the same form again, when you encounter an existing form-session-id, refuse to insert into database

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