// ==UserScript==
// @name           Page Prefetcher
// @namespace      Webnick.UI
// @description    Pre-fetches content from links in a page. Released under the GPL license, http://www.gnu.org/copyleft/gpl.html
//                 Skips mailto:, ftp:, ftps:, chrome: and javascript:
//                 protocols (suggest other protocols to skip please).
//                 Also skips iframes and frames for now.
//                 This is a work in progress.
// @include        *
// ==/UserScript==



(function() {
if (self != top) {
 // skip frames and iframes for now.
 return;
}

// Change this time to whatever you want.
// I found on my PC, 5 seconds (5000 milliseconds) works best.
var preFetchWaitTime = 5000;


// set this to true if you want to see links being processed.
var seePrefetching = false;


var links = self.document.getElementsByTagName("a");
var linksToProcess = [];
var currentLink;
var preFetcher;



if (seePrefetching) {
 var div = document.createElement("div");
 div.style.position = "fixed";
 div.style.top = "0px";
 div.style.left = "0px";
 div.style.width = "600px";
 div.style.height = "100px";
 div.style.overflow = "auto";
 div.style.backgroundColor = "orange";
 div.style.textAlign = "left";
 div.style.padding = "5px";
 document.body.appendChild(div);
}

for (linkIndex = 0; linkIndex < links.length; linkIndex++) {
 currentLink = links[linkIndex].href;

 if (!(/^(mailto:)|(ftp:)|(ftps:)|(chrome:)/i.test(currentLink))
  && !linksToProcess[currentLink]) {
  linksToProcess[linksToProcess.length] = currentLink;
 }
}

setTimeout(
 function preFetch() {
  if (linksToProcess.length > 0) {
   var url = linksToProcess.pop();

   
   if (seePrefetching) {    
    div.innerHTML += "Pre-fetching " + url + "<br />";
   }

   
   preFetcher = document.createElement("iframe");
   preFetcher.src = url;
   preFetcher.id = (new Date()).getTime();
   preFetcher.style.display = "none";
   preFetcher.setAttribute("onload"
   , "setTimeout(function(){top.document.body.removeChild("
    + document.getElementById('" + preFetcher.id + "'))}, 0);");
   document.body.appendChild(preFetcher);
   setTimeout(preFetch, preFetchWaitTime);
  }
 }
 , preFetchWaitTime);
})();