What is this piece of javascript doing?

Discussion in 'Javascript' started by Eqbal, Oct 1, 2004.

  1. Eqbal

    Eqbal Guest

    I have been asked to include this piece of code on certain pages so
    people can track if a user is coming to that page after clicking a
    banner ad. I do not understand how this works. Anyone can explain? I
    don't want to put code on a page I am responsible for without
    following how it works.

    Thanks.

    <div id="lyrDart">
    <!-- Start of DoubleClick Spotlight Tag: Please do not remove-->
    <!-- Creation Date:10/09/03 -->
    <SCRIPT language="JavaScript">
    var axel = Math.random()+"";
    var a = axel * 10000000000000;
    document.write('<IMG
    SRC="http://ad.doubleclick.net/activity;src=865004;type=plasm176;cat=pro50470;ord=1;num='+
    a + '?" WIDTH=1 HEIGHT=1 BORDER=0>');
    </SCRIPT>
    <NOSCRIPT>
    <IMG SRC="http://ad.doubleclick.net/activity;src=865004;type=plasm176;cat=pro50470;ord=1;num=1?"
    WIDTH=1 HEIGHT=1 BORDER=0>
    </NOSCRIPT>
    <!-- End of DoubleClick Spotlight Tag: Please do not remove-->
    </div>
     
    Eqbal, Oct 1, 2004
    #1
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  2. Eqbal

    Hywel Guest

    It looks like it generates a random URL every time the image is loaded.
     
    Hywel, Oct 1, 2004
    #2
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  3. Eqbal

    !lurk Guest

    What Hywel said, but it does that so the URL will not be cached. This
    helps ensure that the number of impressions counted will be accurate.
     
    !lurk, Oct 1, 2004
    #3
  4. Eqbal

    Hywel Guest

    Yup - that's what I meant to say.
     
    Hywel, Oct 1, 2004
    #4
  5. Eqbal

    Fred Oz Guest

    If the user has images turned off in their browser, does DoubleClick
    still count the hit?

    Fred.
     
    Fred Oz, Oct 2, 2004
    #5
  6. Eqbal

    Hywel Guest

    Perhaps. An image will still be displayed.
     
    Hywel, Oct 2, 2004
    #6
  7. [snip]
    No. The request for the image will never be made so they'll never know the
    page was visited by that user.

    Mike
     
    Michael Winter, Oct 2, 2004
    #7
  8. Eqbal

    Eqbal Guest

    Since this script is always present on the page, how does the tracker
    distinguish if the hit is from their banner ad and not just someone
    navigating to the page by some other means?
     
    Eqbal, Oct 6, 2004
    #8
  9. I'm afraid I don't follow the last part of your question. Trackers
    generally don't distinguish anything at all. They just count accesses.

    Mike
     
    Michael Winter, Oct 7, 2004
    #9
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