function checkSome(which)
{
	for(i = 0; i < which.length; i++)
	{
        if(!document.forms[0].elements[ which[i] ].value)
    	{
      		var b = true;
    	}
  	}

    if (b)
    {
    	alert("U bent een verplicht veld vergeten in te vullen!");
     	return false;
    }
    else
    {
     	return true;
    }
}

startList = function()
{
	if (document.all&&document.getElementById)
	{
		var navItems = document.getElementById("nav").getElementsByTagName('li');

		for (i = 0; i < navItems.length; i++)
		{
			navItems[i].oldClass    = navItems[i].className;
			navItems[i].onmouseover = function() { this.className += " over"; }
			navItems[i].onmouseout  = function() { this.className  = this.oldClass; }
		}
	}
}

window.onload=startList;