getSelectedText

http://www.bloglines.com/js/r200702160/prototype/link_search.js

 _getSelectedText: function(limit) {
  var q = '';
  var pos = [0, 0];
  var limit = limit || 200;
  var selectionRefNode = null;
  try {
   if(window.getSelection) {
    var sel = window.getSelection();
    if (sel) {
     var r = null;
     q = sel.toString();
     if (!q) {
      return {text:'', pos:null};
     } else {
      r = sel.getRangeAt(0).cloneRange();
     }
     r.collapse(false);
     selectionRefNode = sel.anchorNode;
     var newNode = document.createElement('span');
     newNode.style.position = 'absolute';
     newNode.style.display = 'inline';
     newNode.style.visibility = 'hidden';
     r.insertNode(newNode);
     pos = Position.cumulativeOffset(newNode);
     Element.extend(newNode).remove();
     r.detach();
    }
   } else if(document.selection) {
    var r = document.selection.createRange();
    q = r.text;
    if (q) {
     selectionRefNode = r.parentElement();
     pos = Position.cumulativeOffset(r);
     pos[0] += document.documentElement.scrollLeft;
     pos[1] += document.documentElement.scrollTop;
     pos[0] += r.boundingWidth;
     // adjust popup mark position
     pos[1] -= 02;
    }
   } else {
    q = '';
   }
   q = q.replace(/((^\s*)|([\n\t\r]+)|(\s*$))/g,'');
   if(q.replace(/[^\x00-\xff]/g,"**").length > limit){
    q = '';
   }
  } catch(e) {
   alert(e);
   q = '';
  }
  var blogIds = null;
  if (selectionRefNode) {
   blogIds = this._getBlogIdsBySelectionNode(selectionRefNode);
  }
  // adjust popup mark position
  pos[0] -= 19;
  pos[1] -= 20;
  return {text:q, pos:pos, ids:blogIds};
 },