function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != "function") {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload)
        oldonload();
      func();
    }
  }
}

// http://www.brainerror.net/scripts_js_blendtrans.php
function opacity(id, opacStart, opacEnd, millisec) {
    //speed for each frame
    var speed = Math.round(millisec / 100);
    var timer = 0;

    //determine the direction for the blending, if start and end are the same nothing happens
    if(opacStart > opacEnd) {
        for(i = opacStart; i >= opacEnd; i--) {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    } else if(opacStart < opacEnd) {
        for(i = opacStart; i <= opacEnd; i++)
            {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    }
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
    var object = document.getElementById(id).style;
    object.opacity = (opacity / 100);
    object.MozOpacity = (opacity / 100);
    object.KhtmlOpacity = (opacity / 100);
    object.filter = "alpha(opacity=" + opacity + ")";
} 

function str2xml(str) {
  return (new DOMParser()).parseFromString(str, "text/xml");
}

function xml2str(xml) {
  return (new XMLSerializer()).serializeToString(xmlobject);
}