Document: hasFocus() method

The hasFocus() method of the Document interface returns a boolean value indicating whether the document or any element inside the document has focus. This method can be used to determine whether the active element in a document has focus.

Syntax

hasFocus()

Parameters

None.

Return value

false if the active element in the document has no focus; true if the active element in the document has focus.

Examples

Checking if the document has focus

The following example checks whether the document has focus or not. A function called checkPageFocus() updates a paragraph element depending on the result of document.hasFocus(). Opening a new window will cause the document to lose focus and switching back to the original window will cause the document to regain focus.

<p id="log">Focus check results are shown here.</p>
<button id="newWindow">Open new window</button>

const body = document.querySelector("body");
const log = document.getElementById("log");

function checkDocumentFocus() {
  if (document.hasFocus()) {
    log.textContent = "This document has focus.";
    body.style.background = "white";
  } else {
    log.textContent = "This document does not have focus.";
    body.style.background = "gray";
  }
}

function openWindow() {
  window.open(
    "https://developer.mozilla.org/",
    "MDN",
    "width=640,height=320,left=150,top=150",
  );
}

document.getElementById("newWindow").addEventListener("click", openWindow);
setInterval(checkDocumentFocus, 300);

Specifications

Browser compatibility

See also

• Document.activeElement
• Using the Page Visibility API