copy-title-and-url-bookmarklet.js

/*
Functionality – when executed, these lines are copied to the clipboard:
1. The URL of the current web page.
2. The title of the current web page (as originally written)
3. The title of the current web page (converted to sentence case with a crude algorithm)
4. Optionally: The currently selected text (if any).

Installation: Create a bookmark whose URL is the code below (including `javascript:{···}`):
– Tested in Chrome and Safari.
– Both browsers can handle URLs with multiple lines.
– The braces create a new local scope so that variables such as `text` are not global. 
*/

javascript:{
  function toSentenceCase(str) {
    return str[0] + str.slice(1).toLocaleLowerCase();
  }

  let text = '';

  text += document.title + '\n';
  text += toSentenceCase(document.title) + '\n';

  text += location.href + '\n';

  const selection = window.getSelection().toString().trim(); /* via @jitterted */
  if (selection.length > 0) {
    text += selection + '\n';
  }

  navigator.clipboard.writeText(text)
  .catch((error) => {
    alert(String(error));
  });
}