Window: confirm() method

message Optional

A string you want to display in the confirmation dialog.

A boolean indicating whether OK (true) or Cancel (false) was selected. If a browser is ignoring in-page dialogs, then the returned value is always false.

The following example shows how to check the returned value of a confirmation dialog. When the user clicks the OK button, we call window.open(), and if the user clicks Cancel, we print some text to a <pre> element.

<button id="windowButton">Open new tab</button>
<pre id="log"></pre>

const windowButton = document.querySelector("#windowButton");
const log = document.querySelector("#log");

windowButton.addEventListener("click", () => {
  if (window.confirm("Do you want to open in new tab?")) {
    window.open("https://developer.mozilla.org/en-US/docs/Web/API/Window/open");
  } else {
    log.innerText = "Glad you're staying!";
  }
});

Dialog boxes are modal windows — they prevent the user from accessing the rest of the program's interface until the dialog box is closed. For this reason, you should not overuse any function that creates a dialog box or a modal window. Alternatively, a <dialog> element can be used for confirmations.

• <dialog> element
• window.alert()
• window.prompt()
• Never Use a Warning When you Mean Undo on A List Apart (2017)