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jump-to-anchor

Context menu item to jump to the closest anchor to the selected text (if any) or to the right-click point otherwise.

  1. // ==UserScript==
  2. // @name jump-to-anchor
  3. // @version 0.2
  4. // @description Context menu item to jump to the closest anchor to the selected text (if any) or to the right-click point otherwise.
  5. // @license MIT
  6. // @author eight04 <eight04@gmail.com>, YFdyh000
  7. // @incompatible chrome
  8. // @incompatible opera
  9. // @incompatible safari
  10. // @include *
  11. // @require https://greasyfork.org/scripts/33034-gm-context/code/GM_context.js?version=219427
  12. // @grant none
  13. // @namespace https://greasyfork.org/users/3017-yfdyh000
  14. // ==/UserScript==
  15.  
  16. /* global GM_context */
  17.  
  18. (function () {
  19.   const all_context = ["page", "selection", "editable", "image", "link"];
  20.   const menuitem = {
  21.     label: "Jump to anchor (from click location)",
  22.     onclick: function() { jumpToAnchor() }
  23.   };
  24.   const menuitem_selected = {
  25.     label: "Jump to anchor (from highlighted selection)",
  26.     onclick: function () { jumpToAnchor() } // TODO: keep the selection
  27.   };
  28.  
  29.   GM_context.add({
  30.     context: all_context,
  31.     items: [menuitem]
  32.   });
  33.   GM_context.add({
  34.     context: all_context,
  35.     items: [menuitem_selected],
  36.     oncontext(e) {
  37.       if (!getSelection()) return false;
  38.     }
  39.   });
  40.  
  41.   function getSelection() {
  42.     return document.getSelection().toString();
  43.   }
  44.   var x, y;
  45.   window.addEventListener('click', function (e) {
  46.     // Avoid grabbing for the actual selection
  47.     // Doesn't seem to execute on single click anyways
  48.     //  but add for good measure
  49.     if (e.button === 2) {
  50.       x = e.clientX;
  51.       y = e.clientY;
  52.     }
  53.   }, true);
  54.   function jumpToAnchor() {
  55.     x = Math.max(0, Math.min(window.innerWidth, x));
  56.     y = Math.max(0, Math.min(window.innerHeight, y));
  57.  
  58.     var node;
  59.     var hasSelection = getSelection();
  60.     if (hasSelection) {
  61.       // For some reason, we can't just check ourselves here for
  62.       //  getSelection().anchorNode, as it is always present
  63.       node = document.getSelection().anchorNode;
  64.     }
  65.     else {
  66.       var caretPosition = document.caretPositionFromPoint(x, y);
  67.       node = caretPosition.offsetNode;
  68.     }
  69.  
  70.     function findDeepestLastChild(elem) {
  71.       var oldElem;
  72.       do {
  73.         oldElem = elem;
  74.         elem = elem.lastElementChild;
  75.       } while (elem);
  76.       return oldElem;
  77.     }
  78.     function foundAnchor(nde) {
  79.       if (nde.id || (nde.name && nde.nodeName.toLowerCase() === 'a')) {
  80.         location.hash = '#' + (nde.id || nde.name);
  81.         return true;
  82.       }
  83.     }
  84.  
  85.     do {
  86.       if (foundAnchor(node)) {
  87.         break;
  88.       }
  89.  
  90.       if (node.previousElementSibling) {
  91.         node = findDeepestLastChild(node.previousElementSibling);
  92.       }
  93.       else {
  94.         node = node.parentNode;
  95.       }
  96.     } while (node);
  97.   }
  98. })();