Image Tracking Doubles Request in Chrome #3
Conversation
… to prevent double trackign in some browser
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Thanks for this! When you say it "can be loaded again" does this mean the problem occurs frequently? I'd like to reproduce it myself before I make the change, and I can't seem to. |
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@malectro Sorry I forgot to include the actual pertinent information. We were not actually seeing the doubled up requests happening in normal usage using the image. One of the mixpanel events happens inside of a onbeforeunload or an unonload, and in Chrome and for whatever reason those seem to trigger double. I found this which somewhat describes the same problem. Small image, non-cached, etc I also think I have a jsfiddle that shows the problems, if you watch the network tab in chrome, or via a proxy you'll see the request double up (there is a third request there as well, but I believe that is jsfiddle's own tracking 😄 ) |
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Wonderful. I made the change in the mixpanel src for the fiddle and it fixed the issue. We'll definitely include it in the next release. |
In Chrome (and potentially others) setting the img.src before appending it to the Dom triggers the img to be loaded. It also can be loaded again when it is attached to the DOM, causing a double track.
Moving the setting of the src till after it is appended alleviates this issue.