var loaded = 0;

function change(Name, No) {
 if (document.images && (loaded == 1)) {
   document [Name].src = eval(Name + No + ".src");
  }
 return true
}

function LoadImgs() {
	if (document.images) {
	  concreteoff = new Image(); concreteoff.src="/images/nav-button.jpg";
	  concreteon = new Image(); concreteon.src="/images/nav-button-h.jpg";
	  constructionoff = new Image(); constructionoff.src="/images/nav-button.jpg";
	  constructionon = new Image(); constructionon.src="/images/nav-button-h.jpg";
	  commercialoff = new Image(); commercialoff.src="/images/nav-button.jpg";
	  commercialon = new Image(); commercialon.src="/images/nav-button-h.jpg";
	  contactoff = new Image(); contactoff.src="/images/nav-button.jpg";
	  contacton = new Image(); contacton.src="/images/nav-button-h.jpg";
	  
	  loaded = 1;
	}
}