User:Mr.Z-man/rollbackSummary.js

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This user script seems to have a documentation page at User:Mr.Z-man/rollbackSummary.

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function rollbackSummary() {
  if (wgAction == "history" || wgPageName == "Special:Contributions" || document.URL.indexOf('&diff=') != -1) {
    var hasRollback = getElementsByClassName(document, "span", "mw-rollback-link");
    if (hasRollback) {
      addPortletLink('p-cactions', 'javascript:setRollbackSummary()', "rollback summary", "ca-rollbacksummary", "Set rollback link edit summary");
    }
  }
}
addOnloadHook(rollbackSummary);
function setRollbackSummary() {
  summary = prompt("Change the default rollback summary for rollback links on this page to:", "");
  if (summary) {
  summary = "&summary=" + summary;
    for (var i in document.links) {
      if (document.links[i].href.indexOf('action=rollback') != -1) {
        document.links[i].href += summary;
      }
    }
  }
}