User:Casper2k3/Javascript/comparelink.js

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Documentation for this user script can be added at User:Casper2k3/Javascript/comparelink.

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/*

*/
// Compare link

function fixCompare()
{
  var histForm=document.getElementsByTagName("form")[0];
  var finalButton=document.getElementById("historysubmit");
  var firstButton=histForm.getElementsByTagName("input")[1];
  histForm.removeChild(finalButton);
  histForm.removeChild(firstButton);
  var compareLink=document.createElement("a");
  var genLink="http://en.wikipedia.org/w/index.php?title=" + histForm.title.value + "&diff=" + histForm.diff[0].value + "&oldid=" + histForm.oldid[1].value;
  compareLink.setAttribute("href", genLink);
  compareLink.appendChild(document.createTextNode("Compare selected versions"));
  histForm.insertBefore(compareLink, document.getElementById("pagehistory"));
  var endLink=compareLink.cloneNode(true);
  histForm.appendChild(endLink);
  var diffList=document.getElementById("pagehistory");
  diffList.setAttribute("onchange", "updateCompare()");
}
function updateCompare()
{
  var histForm=document.getElementsByTagName("form")[0];
  var diffList=document.getElementById("pagehistory");
  var compareLink=diffList.previousSibling;
  var endLink=diffList.nextSibling;
  var oldInd=-1;
  var i=0;
  while(oldInd==-1 & i<histForm.oldid.length)
  {
    if(histForm.oldid[i].checked)
      oldInd=i;
    i++;
  }
  var diffInd=-1;
  var j=0;
  while(diffInd==-1 & j<histForm.diff.length)
  {
    if(histForm.diff[j].checked)
      diffInd=j;
    j++;
  }
var genLink="http://en.wikipedia.org/w/index.php?title=" + histForm.title.value + "&diff=" + histForm.diff[diffInd].value + "&oldid=" + histForm.oldid[oldInd].value;
  compareLink.setAttribute("href", genLink);
  endLink.setAttribute("href", genLink);
}
if(url.indexOf("action=history")!=-1)
$(fixCompare);
/*

*/