Oracle Apex Upload and Preview Image

Reference 1st : https://www.youtube.com/watch?v=XTao_pQALLg

code in post-text of "FILE BROWSER"  :

<canvas id="image-preview"      width="100" height="50" style="border:1px solid #000000;">

Dynamic Action  of "File Browser": CHANGE AND JAVA SCRIPT CODE :

try {
var canvus =$x('image-preview');
var ctx = canvus.getContext('2d');
var img = new Image;

img.src = window.URL.createObjectURL(this.triggeringElement.files[0]);
img.onload = function() {
 if (img.width > 200) {
   canvus.style.width = "100px";
 }
 canvus.width = img.width;
 canvus.height = img.height;
 ctx.drawImage(img,0,0);
 $("#container-img-preview").show();
}
} catch (e) {
console.log(e);
}