[jquery] How to get span tag inside a div in jQuery and assign a text?

I use the following ,

<div id='message' style="display: none;">
  <span></span>
 <a href="#" class="close-notify">X</a>
</div>

Now i want to find the span inside the div and assign a text to it...

function Errormessage(txt) {
    $("#message").fadeIn("slow");
    // find the span inside the div and assign a text
    $("#message a.close-notify").click(function() {
        $("#message").fadeOut("slow");
    });
}

function Errormessage(txt) {
    $("#message").fadeIn("slow");
    $("#message span:first").text(txt);
    // find the span inside the div and assign a text
    $("#message a.close-notify").click(function() {
        $("#message").fadeOut("slow");
    });
}

$("#message > span").text("your text");

or

$("#message").find("span").text("your text");

or

$("span","#message").text("your text");

or

$("#message > a.close-notify").siblings('span').text("your text");

Vanilla JS, without jQuery:

document.querySelector('#message span').innerHTML = 'hello world!'

Available in all browsers: https://caniuse.com/#search=querySelector

Try this

$("#message span").text("hello world!");

function Errormessage(txt) {
    var elem = $("#message");
    elem.fadeIn("slow");
    // find the span inside the div and assign a text
    elem.children("span").text("your text");

    elem.children("a.close-notify").click(function() {
        elem.fadeOut("slow");
    });
}