// normal state should be FILENAME.gif and rollover should be FILENAME_r.gif

function preload() {
  if (document.images) {
  
    // replace with the image file names without the extension
    
    nav_images = new Array("home", "about", "products", "manufacturing", "mat-datasheet", "links", "credit", "contact", "testimonial");
    for(i=0;i<nav_images.length;i++) {
      newimg = new Image();
      newimg.src = "/images/nav/"+nav_images[i]+".gif";
      newimg = new Image();
      newimg.src = "/images/nav/"+nav_images[i]+"_r.gif";
    }
    return 1;
  }
  return 0;
}

function rollOn(img, doneloading) {
    var loaddone = typeof(doneloading);
    if (document.images && loaddone!= "undefined") {
      var typeofImg = eval("typeof(document.images['"+img+"'])");
      if(typeofImg!="undefined") {
        if(doneloading==1) {
          eval("document."+img+".src = '/images/nav/"+img+"_r.gif'");
          curRoll = img;
        }
      }
    }
  }

function rollOff(img, doneloading) {
    var typeofImg = eval("typeof(document.images['"+img+"'])");
    if(typeofImg!="undefined") {
      var loaddone = typeof(doneloading);
      if (document.images && loaddone!= "undefined") {
        if(doneloading==1)
          eval("document."+img+".src = '/images/nav/"+img+".gif'");
      }
    }
  }

window.onload = function() {
  doneloading = preload();
}