Please see here.
Here are some factors that affect how fast the resize will be executed:
* Whether the resize is triggered by the user action;
* Whether the resize is requested for a currently active ad;
* Whether the resize is requested for an ad below the viewport or above the viewport.
In the demo on the right, you will notice that if
a) the user doesn't interact at all with the ad and the ad is below the viewport, the ad will resize after a 3 second timeout (which is specific to the creative code for demo purposes)
b) the user immediately scrolls down so the ad is in the viewport, front and center, the ad will not resize
c) the user immediately scrolls down, but interacts with the ad by clicking on it, the ad will resize within 3 seconds (again, a timeout delay introduced in the creative for demo purposes).
See creative details image.
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