How to copy to the clipboard in JavaScript?

Automatic copying to clipboard may be dangerous, therefore most browsers (except IE) make it very difficult. Personally, I use the following simple trick:

function copyToClipboard (text) {
  window.prompt ("Copy to clipboard: Ctrl+C, Enter", text);
}

The user is presented with the prompt box, where the text to be copied is already selected. Now it’s enough to press Ctrl+C and Enter (to close the box) — and voila!

Now the clipboard copy operation is SAFE, because the user does it manually (but in a pretty straightforward way). Of course, works in all browsers.