function retorna_link(numero)
{
	if(numero == 1) return 'extrusao';
	else if(numero == 2) return 'home';
}
	
function mouse_entra(id) {

	var num;
	for(num = 1; num < 4; num++)
	{
		if(id != retorna_link(num)) document.getElementById(retorna_link(num)).style.display = 'none';
		else document.getElementById(retorna_link(num)).style.display = 'inline';

	}
 
}

<!--
<!--
function MM_reloadPage(init) {  //reloads the window if Nav4 resized
  if (init==true) with (navigator) {if ((appName=="Netscape")&&(parseInt(appVersion)==4)) {
    document.MM_pgW=innerWidth; document.MM_pgH=innerHeight; onresize=MM_reloadPage; }}
  else if (innerWidth!=document.MM_pgW || innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);
// -->

function MM_findObj(n, d) { //v4.0
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && document.getElementById) x=document.getElementById(n); return x;
}

function MM_showHideLayers() { //v3.0
  var i,p,v,obj,args=MM_showHideLayers.arguments;
  for (i=0; i<(args.length-2); i+=3) if ((obj=MM_findObj(args[i]))!=null) { v=args[i+2];
    if (obj.style) { obj=obj.style; v=(v=='show')?'visible':(v='hide')?'hidden':v; }
    obj.visibility=v; }
}
//-->


function mostra_popup() {
	window.open('http://www.hydroacro.com.br/boletim/index.html', '', 'toolbar=0,scrollbars=1,location=0,statusbar=0,menubar=0,resizable=1,width=819,height=500');
}

//imagens
function init() {
  if (!document.getElementById) return
  var imgOriginSrc;
  var imgTemp = new Array();
  var imgarr = document.getElementsByTagName('img');
  for (var i = 0; i < imgarr.length; i++) {
    if (imgarr[i].getAttribute('hsrc')) {
        imgTemp[i] = new Image();
        imgTemp[i].src = imgarr[i].getAttribute('hsrc');
        imgarr[i].onmouseover = function() {
            imgOriginSrc = this.getAttribute('src');
            this.setAttribute('src',this.getAttribute('hsrc'))
        }
        imgarr[i].onmouseout = function() {
            this.setAttribute('src',imgOriginSrc)
        }
    }
  }
}
onload=init;

function MM_openBrWindow(theURL,winName,features) { //v2.0
  window.open(theURL,winName,features);
}