Adding selected text to the reply

boards/static/js/thread.js

@@ -36,6 +36,11 b' function moveCaretToEnd(el) {'
 
 function addQuickReply(postId) {
     var textToAdd = '>>' + postId + '\n\n';
+    var selection = window.getSelection().toString();
+    if (selection.length > 0) {
+        textToAdd += '> ' + selection;
+    }
+
     var textAreaId = 'textarea';
     $(textAreaId).val($(textAreaId).val()+ textToAdd);