Display images from firebase storage in html img tags

The bellow two lines which is commented are not required, I have tested. it is working fine.

//var path = spaceRef.fullPath;
//var gsReference = storage.refFromURL('gs://test.appspot.com')

    <script>
     function showimage() {



         var storageRef = firebase.storage().ref();
         var spaceRef = storageRef.child('sweet_gift/vytcdc.png');
         storageRef.child('sweet_gift/vytcdc.png').getDownloadURL().then(function(url) {
             var test = url;
             alert(url);
             document.querySelector('img').src = test;

         }).catch(function(error) {

         });


     }
    </script>
    <input type="button" value ="view Image" id="viewbtn" onclick="showimage();">
    <img src="test" height="125px" width="200px"/> 

Once you have the test variable, you need to set the image's src to it using a script.

Something like this:

//var storage    = firebase.storage();
//var storageRef = storage.ref();
//var spaceRef = storageRef.child('images/photo_1.png');
//
//storageRef.child('images/photo_1.png').getDownloadURL().then(function(url) {
//
//
//  var test = url;
//  add this line here:
//  document.querySelector('img').src = test;
//
//}).catch(function(error) {
//
//});
//
var test = 'firebase_url';

document.querySelector('img').src = test;

<img height="125" width="50"/>