SO this is my code so far:

JS:

        <script type="text/javascript">
            function Hide(srcField)
            {
                var x = srcField.getAttribute('name');
                var string = new RegExp("hide_ID",'gi');

                switch (x)
                {
                    case "1":
                    var dataRows= document.getElementsByID("obrazovanje");
                    alert (dataRows[0].innerHTML);
                    dataRows[0].className.replace('',string);
                    break;
                    case "2":
                    var dataRows= document.getElementsByID("rad_iskustvo");
                    dataRows[0].className.replace('',string);
                    break;
                    case "3":
                    var dataRows= document.getElementsByID("strani_jezici");
                    dataRows[0].className.replace('',string);
                    break;
                    case "4":
                    var dataRows= document.getElementsByID("znanja_vjestine");
                    dataRows[0].className.replace('',string);
                    break;
                    case "5":
                    var dataRows= document.getElementsByID("osobine_interesi");
                    dataRows[0].className.replace('',string);
                    break;
                }
            }
    </script>

CSS:

.hide_ID,
{
display:none
}

HTML:

    <a name="1"><h4><span name="1" onmouseover="Hide(this)">OBRAZOVANJE:</span></h4></a>

    <div ID="obrazovanje">
    <ul>
    <li>2001.-2005.  elektrotehnicar</li>
    <li>2009.-2012.   racunarstvo</li>
    </ul>
    </div>

the idea is that i want to hide the div block when i hover over the title that's in h4, but it doesn't seem to hide it... any ideas? i started using replace but it still didn't work, before that it was just 'dataRows[0].className = "hide_ID"' but that didn't work either.