if (document.images) {

  homeOn = new Image();
  homeOn.src = "images/button_home-on.gif"

  homeOff = new Image();
  homeOff.src = "images/button_home.gif"

  companyOn = new Image();
  companyOn.src = "images/button_company-on.gif"

  companyOff = new Image();
  companyOff.src = "images/button_company.gif"

  productsOn = new Image();
  productsOn.src = "images/button_products-on.gif"

  productsOff = new Image();
  productsOff.src = "images/button_products.gif"

  pressOn = new Image();
  pressOn.src = "images/button_press-on.gif"

  pressOff = new Image();
  pressOff.src = "images/button_press.gif"

  resourcesOn = new Image();
  resourcesOn.src = "images/button_resources-on.gif"

  resourcesOff = new Image();
  resourcesOff.src = "images/button_resources.gif"

  contactOn = new Image();
  contactOn.src = "images/button_contact-on.gif"

  contactOff = new Image();
  contactOff.src = "images/button_contact.gif"



  descriptionOn = new Image();
  descriptionOn.src = "images/description_blank.gif"

  descriptionOff = new Image();
  descriptionOff.src = "images/description_blank.gif"

  descriptionA = new Image();
  descriptionA.src = "images/description_company.gif"

  descriptionB = new Image();
  descriptionB.src = "images/description_products.gif"

  descriptionC = new Image();
  descriptionC.src = "images/description_press.gif"

  descriptionD = new Image();
  descriptionD.src = "images/description_resources.gif"

  descriptionE = new Image();
  descriptionE.src = "images/description_contact.gif"

  descriptionF = new Image();
  descriptionF.src = "images/description_home.gif"

}

function changeImages() {
	if (document.images) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
      	document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
    	}
  	}
}

var popup_window = null;

function popup(status,url) {
	if(status != 0) {
   	if(popup != null) {
      	popup.OnTopWindow();

      } else {
         var popup = open(url, "Popup", "width=525,height=350,resizable=1,scrollable=yes, scrollbars=yes");
         popup_window = popup;
/*
 <!--
      } else {
        if(popup_window != null) popup_window.close();
-->
*/
     }
   }
}

<!-- script start
function urljump(url) {
	top.window.location = url;
}
// script end -->