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1111Re: [OLmws] How can I use AJAX in overlibmws? Thanks,

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  • dogshasha
    Mar 2, 2008
    • 0 Attachment
      Hi Fote, Thank you so much for explaining it in such details. One more
      question, if I'm using overlib to display some simple text, images with
      some caption, nothing fancy, can I switch to overlibmws without having
      to change my code? Thanks,

      Best Regards,

      Michael
      --- In overlibmws@yahoogroups.com, "Foteos Macrides" <fote@...> wrote:
      >
      > Michael,
      >
      > The support document for AJAX in general, and for use of the OLgetAJAX
      or OLpostAJAX functions via the ajaxcontentmws.js support script, is:
      >
      > http://www.macridesweb.com/oltest/AJAX.html
      >
      > Note that if you already are using AJAX via an equivalent function in
      one of the popular libraries for AJAX, e.g., prototype or mootools, you
      can continue using that with overlibmws popups, as also is discussed in
      the above support document.
      >
      > Also note that in addition to the Command Reference for overlibmws, a
      large number of support documents including the above can be accessed
      via:
      >
      > http://www.macridesweb.com/oltest/
      >
      > Note as well that you do not need to use AJAX to achieve your
      objective of not fetching the full-sized image specified via an img tag
      in the lead argument of your overlib function call during initial
      loading of the document. The thumbnail will be fetched for direct
      display within your document while the document is being loaded, but
      unless you use javascript pre-loading code (see below) the full-sized
      image will not be fetched from your server until the first time (if
      ever) that the user clicks on the thumbnail (and then for any subsequent
      invocations of that popup, the cached, local copy of the full-sized
      image will be used).
      >
      > Be sure to indicate both the width and height of the full-sized image
      in the img tag so that the popup will be properly sized before the image
      has been fetched, rather than requiring any re-draw of the popup after
      the image has been received and its height and width can be read by the
      browser from the image's own header section. You similarly would be
      wise to indicate the height and width for your thumbnail(s), to avoid
      any need for redraws of the document in conjunction with its initial
      loading.
      >
      > Since you are using the onclick event to invoke the popup with the
      full-sized image, you might wish also to include markup for invoking a
      descriptive popup via the onmouseover event, as discussed in the Getting
      Started:
      >
      > http://www.macridesweb.com/oltest/STARTED.html
      >
      > support document. Also, be sure to structure your onclick attribute
      value so that it returns false, to ensure a complete fetch and loading
      of the full-sized image, as explained in the:
      >
      > http://www.macridesweb.com/oltest/ONCLICK.html
      >
      > support document.
      >
      > Normally, one includes pre-loading javascript code for images which
      will appear only in popups, as discussed and illustrated in the:
      >
      > http://www.macridesweb.com/oltest/STICKY.html
      >
      > support document. For your presumably quite large, full-sized images,
      one would put a script block with the pre-loading code at the bottom of
      your document's body section, rather than including it in a script block
      in the document's head section as is done for the small images in that
      support document, so that the fetching of those full-size images will
      not commence until all other fetches associated with loading the
      document have been initiated (modern browsers issue and maintain up to 6
      simultaneous requests to the server when the document is loading, but
      even so, it's a good idea to make sure requests for very large images
      which are used only in popups will be issued last). All of the modern
      browsers start displaying the document before it has been fully loaded,
      and before images associated with pre-loading code have actually be
      fetched. The overlibmws library in turn is structured such that its
      popups can be invoked as soon as the associated portions of the document
      are displayed, without need for the document to have as yet been fully
      loaded or for any of the images associated with pre-loading code to have
      been fetched. So most people do include such pre-loading code, so that
      the images are likely to be in local cache and thus displayed promptly
      upon invocations -- including the first invocation -- of popups which
      contain images. There is, however, a "wasted bandwidth" cost for
      pre-loading images which are never shown because the user did not invoke
      the associated popups, so if you are using a hosting service whose
      monthly bandwidth allotment is on the smallish side, that's a factor in
      deciding whether to use pre-loading for your full-sized images.
      >
      > Once you've set up all that, you'll likely next want to know how to
      give users the option to print your DHTML popups with those images.
      That's explained in the:
      >
      > http://www.macridesweb.com/oltest/PRINT.html
      >
      > support document set. And be sure to check out Manon's beautiful
      examples:
      >
      > http://www.purplespirit.com/overlib/ol_print.htm
      >
      > of thumbnail image galleries.
      >
      > Fote
      > --
      >
      > ----- Original Message -----
      > From: dogshasha
      > To: overlibmws@yahoogroups.com
      > Sent: Saturday, March 01, 2008 3:21 PM
      > Subject: [OLmws] How can I use AJAX in overlibmws? Thanks,
      >
      >
      > I'm referred here by Overlib support group.
      >
      > There is an AJAX plugin but I can't find any documentations about
      it. So please bear with me.
      >
      > Here is what I want to do. I like to display an image thumbnail on
      the web and show the real big-sized image by clicking on it. I think
      this concept falls into AJAX. Can someone here shed any light on how to
      do it? Thanks in advance,
      >
      > Michael
      >
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