The .data() function returns inconsistent values:

If you try to load a not-existing-value of an object, which does not have ANY values stored, it will return null.

But if this object has ANY value stored in it, and you load the not-existing-value, it returns "undefined".

Example:

<div id="div1">test</div>

<script type="text/javascript">

console.log($("#div1").data("test")); -> result: null

$("#div1").data("abcdefg", 1);

console.log($("#div1").data("test")); -> result: 'undefined'

</script>

That's not what it should be like, is it?