function set_visible(elem, should_show) {
    if (should_show)
        YAHOO.util.Dom.removeClass(elem, 'invisible');
    else
        YAHOO.util.Dom.addClass(elem, 'invisible');
}

function $(szId) {
    return YAHOO.util.Dom.get(szId);
}

 function is_numeric(str_test)
{
	var valid_chars = "0123456789.";
   	var c;

 	for (i = 0; i < str_test.length; i++) 
    { 
		c = str_test.charAt(i); 
		if (valid_chars.indexOf(c) == -1) 
        {
			return false;
		}
	}
	return true;
}
  
function trim(str)
{
   return str.replace(/^\s*|\s*$/g,"");
}
  
function highlight_element(elementId, highlight)
{
	elem = document.getElementById(elementId);
	if(highlight)
		elem.style.color = "red";
	else
		elem.style.color = "black";
}

function is_valid_email(str)
{
	return (str.lastIndexOf(".") > 2 && str.indexOf("@") > 0);
}

function addEvent(obj, type, fn) {
  if (obj.addEventListener)
    obj.addEventListener(type, fn, false);
  else if (obj.attachEvent) {
    obj["e"+type+fn] = fn;
    obj[type+fn] = function() { obj["e"+type+fn](window.event); }
    obj.attachEvent("on"+type, obj[type+fn]);
  }
}

function toggle_box(szDivID, iState) // 1 visible, 0 hidden
{
    if(document.layers)	   //NN4+
    {
       document.layers[szDivID].visibility = iState ? "show" : "hide";
    }
    else if(document.getElementById)	  //gecko(NN6) + IE 5+
    {
        var obj = document.getElementById(szDivID);
        obj.style.visibility = iState ? "visible" : "hidden";
    }
    else if(document.all)	// IE 4
    {
        document.all[szDivID].style.visibility = iState ? "visible" : "hidden";
    }
}