Speed up loading when the drop down list is long
<p>I am making a drop down list with html ul li. And the list length is over 500. The list data is loaded on <code>window.onload</code>. The height of the ul is fixed (300px). When pulling down the drop down list, the list is blank at first and the data will be loaded in quite a few seconds. The question is how to avoid the loading time. </p>