Detect the Enter key in a text input field

$(".input1").on('keyup', function (e) {
    if (e.key === 'Enter' || e.keyCode === 13) {
        // Do something
    }
});

// e.key is the modern way of detecting keys
// e.keyCode is deprecated (left here for for legacy browsers support)
// keyup is not compatible with Jquery select(), Keydown is.

event.key === "Enter"

More recent and much cleaner: use event.key. No more arbitrary number codes!

NOTE: The old properties (.keyCode and .which) are Deprecated.

const node = document.getElementsByClassName("input1")[0];
node.addEventListener("keyup", function(event) {
    if (event.key === "Enter") {
        // Do work
    }
});

Modern style, with lambda and destructuring

node.addEventListener("keyup", ({key}) => {
    if (key === "Enter") {
        // Do work
    }
})

If you must use jQuery:

$(document).keyup(function(event) {
    if ($(".input1").is(":focus") && event.key == "Enter") {
        // Do work
    }
});

Mozilla Docs

Supported Browsers

$(document).keyup(function (e) {
    if ($(".input1:focus") && (e.keyCode === 13)) {
       alert('ya!')
    }
 });

Or just bind to the input itself

$('.input1').keyup(function (e) {
    if (e.keyCode === 13) {
       alert('ya!')
    }
  });

To figure out which keyCode you need, use the website http://keycode.info