Trigger a keypress/keydown/keyup event in JS/jQuery?

Question

What is the best way to simulate a user entering text in a text input box in JS and/or jQuery?

I don\'t want to actually put text in the input box,

Answer 1

You can achieve this with: EventTarget.dispatchEvent(event) and by passing in a new KeyboardEvent as the event.

For example: element.dispatchEvent(new KeyboardEvent('keypress', {'key': 'a'}))

Working example:

// get the element in question
const input = document.getElementsByTagName("input")[0];

// focus on the input element
input.focus();

// add event listeners to the input element
input.addEventListener('keypress', (event) => {
  console.log("You have pressed key: ", event.key);
});

input.addEventListener('keydown', (event) => {
  console.log(`key: ${event.key} has been pressed down`);
});

input.addEventListener('keyup', (event) => {
  console.log(`key: ${event.key} has been released`);
});

// dispatch keyboard events
input.dispatchEvent(new KeyboardEvent('keypress',  {'key':'h'}));
input.dispatchEvent(new KeyboardEvent('keydown',  {'key':'e'}));
input.dispatchEvent(new KeyboardEvent('keyup', {'key':'y'}));

<input type="text" placeholder="foo" />

MDN dispatchEvent

MDN KeyboardEvent

Answer 2

You're now able to do:

var e = $.Event("keydown", {keyCode: 64});

Answer 3

To trigger an enter keypress, I had to modify @ebynum response, specifically, using the keyCode property.

e = $.Event('keyup');
e.keyCode= 13; // enter
$('input').trigger(e);

Answer 4

For typescript cast to KeyboardEventInit and provide the correct keyCode integer

const event = new KeyboardEvent("keydown", {
          keyCode: 38,
        } as KeyboardEventInit);

Answer 5

I thought I would draw your attention that in the specific context where a listener was defined within a jQuery plugin, then the only thing that successfully simulated the keypress event for me, eventually caught by that listener, was to use setTimeout(). e.g.

setTimeout(function() { $("#txtName").keypress() } , 1000);

Any use of $("#txtName").keypress() was ignored, although placed at the end of the .ready() function. No particular DOM supplement was being created asynchronously anyway.

Answer 6

Here's a vanilla js example to trigger any event:

function triggerEvent(el, type){
if ('createEvent' in document) {
        // modern browsers, IE9+
        var e = document.createEvent('HTMLEvents');
        e.initEvent(type, false, true);
        el.dispatchEvent(e);
    } else {
        // IE 8
        var e = document.createEventObject();
        e.eventType = type;
        el.fireEvent('on'+e.eventType, e);
    }
}