trigger an event when an element reaches a position on the screen
<p>I would like to trigger some functions according to a position of an element. This element's position changes every tenth second.  There is two dozens functions to trigger.</p>

<p>I thought about this pseudo-code :</p>

<pre><code>When element position changes{
  Loop through all the coordinates to see if a function can be triggered{
     if the current element position matches the function's triggering position 
         execute the function
     }
}
</code></pre>

<p>But looping through all possible position each split seconds burdens the browser. So if there is a way to have events to do that.</p>

<p>Is it possible ?</p>

<p>Edit:
After Beetroot-Beetroot comment, I must say that the element that moves only moves on an X abscissa : so just one dimension.</p>

<p>It's much like a horizontal timeline moving from left to right, where some animation happen when a certain year is reached.
However the moving speed can be increased by the user, so fixed time to trigger animation is not an option.</p>
