detect currently selected input field in javascript for bookmarklet

Question

I am trying to write a bookmarklet that fills the currently selected field in with a function of today's date. How do I find the currently tabbed to or selected input field using javascript?

Answer 1

To get the active element you can use

var input = document.activeElement;

if (input.tagName == "INPUT" || input.tagName == "TEXTAREA")
{
    input.value = "today's date";
}

Answer 2

You can use

document.activeElement

To get the current active element.

Then you can use it to input the data, like so

if (document.activeElement.nodeName === 'INPUT') {
   document.activeElement.value = new Date().getTime();
}

But your better off adding a focus event to the element