JAVASCRIPT

click button when press enter javascript

var input = document.getElementById("myInput");

// Execute a function when the user releases a key on the keyboard
input.addEventListener("keyup", function(event) {
  // Number 13 is the "Enter" key on the keyboard
  if (event.keyCode === 13) {
    // Cancel the default action, if needed
    event.preventDefault();
    // Trigger the button element with a click
    document.getElementById("myBtn").click();
  }
});

on enter press button

<input onkeyup="if(event.keyCode===13){submit.click()}"><button id="submit">submit</button>

button onclick enter key

$("#id_of_textbox").keyup(function(event) {
    if (event.keyCode === 13) {
        $("#id_of_button").click();
    }
});

Trigger a button click with JavaScript on the Enter key in a text box

### please check the source for in detail explanation ###
In jQuery, the following would work:

$("#id_of_textbox").keyup(function(event) {
    if (event.keyCode === 13) {
        $("#id_of_button").click();
    }
});
$("#pw").keyup(function(event) {
    if (event.keyCode === 13) {
        $("#myButton").click();
    }
});

$("#myButton").click(function() {
  alert("Button code executed.");
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Username:<input id="username" type="text"><br>
Password:&nbsp;<input id="pw" type="password"><br>
<button id="myButton">Submit</button>
Or in plain JavaScript, the following would work:

document.getElementById("id_of_textbox")
    .addEventListener("keyup", function(event) {
    event.preventDefault();
    if (event.keyCode === 13) {
        document.getElementById("id_of_button").click();
    }
});
document.getElementById("pw")
    .addEventListener("keyup", function(event) {
    event.preventDefault();
    if (event.keyCode === 13) {
        document.getElementById("myButton").click();
    }
});

function buttonCode()
{
  alert("Button code executed.");
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Username:<input id="username" type="text"><br>
Password:&nbsp;<input id="pw" type="password"><br>
<button id="myButton" onclick="buttonCode()">Submit</button>