Image and Video pre-load for graphical stimulus control in questfox

With the new features of questfox more and more users are incorporating graphical stimuli into survey with exact time measurement. Some projects use more than 20 MB of graphical material during one survey. Even though we would always recommend to compress the data to the maximum possible still there is the issue of loading time of graphical material.

Our development team is happy to announce the integration of a background pre-loading mechanism for graphical stimuli inside of questfox.

The snippet can be integrated in any HTML question page in your questfox project. Just make sure that you allow enough time for your stimulus material to be loaded before showing it to your respondents.

This is the snippet that you might want to put into a hidden question inside of a questfox question. Please make sure, that you exchange the filenames with the right directory.

<!–
var images = new Array()
function preload(FILENAME:here) {
for (i = 0; i

In case you want to test a video in the survey it makes sense to pre-load this video into the cache of a participant’s browser before you show it later by using the style=”display: none;”.

<p><video style="display: none;" src="https://YOUTVIDEOFILE.mp4" autoplay="autoplay" muted="" width="300" height="150"> </video></p>