Copy text to clipboard from bookmarklet

There is a nice little bookmarket in Github Gist that does the core of what you want -- copying to the clipboard. It does not use any external libraries, which I think of as an advantage.

As written, it copies some static text, but toward the bottom it talks about adapting it to other uses, such as copying the page title.

Since you've stated that 'The extraction is easy enough ...', you should be easily be able to adapt that gist to what you want to do.

I tried the plain vanilla version of the bookmarklet, because I have some static text that I often need to transfer to my clipboard. It works very well in Chrome 61 with no modifications. But make sure you read the comments; some people have suggestions on getting it to work in other browsers and scenarios.

Here is the code that I tested, already minified and ready to turn into a bookmarklet:

javascript:!function(a){var b=document.createElement("textarea"),c=document.getSelection();b.textContent=a,document.body.appendChild(b),c.removeAllRanges(),b.select(),document.execCommand("copy"),c.removeAllRanges(),document.body.removeChild(b)}("Text To Copy");

Gist has the pre-minified code as well.

With recent versions of Firefox, interacting with the clipboard via a bookmarklet in general won't work due to missing permissions (see this information for more details). There may be a way, however, to have the bookmarklet display a button, and perform the clipboard interaction in the context of a button-click event handler.

A possibly more straightforward solution is to use a user-script manager, and define your bookmarklet in the form of a user-script that you can activate via a keyboard combination. See, for example this user script, reproduced here for completeness:

// Add the following as a user-script (via an extension like https://github.com/violentmonkey/violentmonkey) in order to copy the
// current webpage and selected text to the clipboard in a format suitable for pasting into an org-mode document.
// To execute the action, you need to press Alt-C on a webpage, though this can be modified by changing the keycode
// used in the onkeyup function.

// ==UserScript==
// @name Copy Org-mode Link
// @namespace Violentmonkey Scripts
// @match *://*/*
// @grant clipboardWrite
// ==/UserScript==

function main() {
    function copyTextToClipboard(text) { var textArea = document.createElement("textarea"); textArea.style.position = 'fixed'; textArea.style.top = 0; textArea.style.left = 0; textArea.style.width = '2em'; textArea.style.height = '2em'; textArea.style.padding = 0; textArea.style.border = 'none'; textArea.style.outline = 'none'; textArea.style.boxShadow = 'none'; textArea.style.background = 'transparent'; textArea.value = text; document.body.appendChild(textArea); textArea.select(); try { var successful = document.execCommand('copy'); var msg = successful ? 'successful' : 'unsuccessful'; console.log('Copying text command was ' + msg); } catch (err) { console.log('Oops, unable to copy'); } document.body.removeChild(textArea); }; var url = encodeURIComponent(location.href); url = url.replace(/%253A/g, ':').replace(/%252F/g, '/'); var title = document.title; title = title.replace(/\[/g, '{'); title = title.replace(/\]/g, '}'); var sel_text = window.getSelection(); copyTextToClipboard('[['+url+']['+title+']]'+'\n\n'+sel_text);
}

// listen for Alt-C key-combination, and then execute
document.onkeyup=function(e){
    var e = e || window.event; // for IE to cover IEs window object
    if(e.altKey && e.which == 67) {
         main();
         return false;
    }
}

Since the new Clipboard API, this is easy in browsers that support it:

javascript: navigator.clipboard.writeText('some text from somewhere');null;

Caveat: Any alerts or prompts in your bookmarklet will cause the document to lose focus, and the clipboard API will become unavailable. In that case you need to move focus back into the document before any subsequent clipboard operations will work:

const oldFocus = document.activeElement; 
/* do popup stuff here */
oldFocus.focus(); 
/* do clipboard stuff here */