The button demonstrates that ablility. Use the button’s onclick code wherever you need.
<div id="flag-name" style="hidden">en-flag.jpg</div>
<img id="myImage" />
<button onclick="document.getElementById('myImage').src=document.getElementById('flag-name').innerText">Change</button>You can simply do it in jQuery by getting the text of the div and then setting the source of image like this:
var source = $("#flag-name").text();
console.log("before - " + $("#image").attr("src"));
$("#image").attr("src",source);
console.log("after - " + $("#image").attr("src"));<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="flag-name" style="hidden">en-flag.jpg</div>
<img id="image" src="https://stackoverflow.com/questions/48871589/DIV CONTENTS HERE">You need an event to start the jQuery/javascript — so I added a button. Also, you will find it easier to target specific DIV and IMG tags if you give them IDs or classes.
$('button').click(function(){
var mySrc = $('#flag-name').text();
$('img').attr('src', mySrc);
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="flag-name" style="hidden">http://placeimg.com/300/200/animals</div>
<img src="https://stackoverflow.com/questions/48871589/DIV CONTENTS HERE">
<button>Go</button>