Paste into CodeMirror not working in my application


Paste from the clipboard into a CodeMirror (textarea) instance in my application/web page is not working. I have successfully pasted in a standalone (test) page, so it must be something that I am doing in the page. I am using version 5.25.2, and have tested this in Chrome (current - version Version 60.0.3112.113) and Firefox (current - version 55.0.3).

In the page, CodeMirror is instantiated for a jquery dialog window - triggered when a menu selection is made, where the html - containing the textarea used for CodeMirror - is generated dynamically.

ie. (a snippet)
var html = ‘<div id=“node-edit-codemirror-editor-div”>’
+ ‘<textarea id=“node-edit-codemirror-editor” name=“node-edit-codemirror-editor” rows=“2” cols=“50”>’ + template_content + ‘’
+ ‘</div>’;
codemirror_editor = CodeMirror.fromTextArea(document.getElementById(“node-edit-codemirror-editor”), {
mode: {name: “python”,
version: 2,
singleLineStringErrors: false},
lineNumbers: true,
indentUnit: 4,
matchBrackets: true,
autoRefresh: true

$("#show-template-editor-dialog").dialog(…); – displays the window

Is there any option I should add to enable this?

I tried adding a ‘paste’ listener, but this does nothing - the handler function never gets called

document.addEventListener(“paste”, onPaste);

function onPaste(e) {


I also tried a ‘keydown’ handler, which does get called, but has no clipboard data.

Please help. What am I missing?

Colin Goldberg

Nope, paste should work out of the box. You could try editing your setup to be closer and closer to the demo pages, and seeing where paste starts working.

The strange thing is that I also use tinymce inside this page, and it
pastes ok. CodeMirror must be implementing this differently than tinymce.

(I use tinymce for html & text, and I would like to use CodeMirror for
python, pyspark, json, yaml, sql, scala, and possibly others.)

Colin Goldberg

I have reduced the problem to its basic elements - the same piece of code works in a standalone page, and does not work inside my application page.

Can you possibly point me to what I should look at here - I am stumped. Otherwise this seems like a showstopper to me - which would be a pity because CodeMirror is a really useful library.

I’d try removing CSS to see if that has an effect. And if it does, add it back piece by piece to figure out the problematic rule.