In these tutorials, we are creating a preview of an image before uploading it with javascript. It is a very short tutorial but there you can learn the basics of uploading and previewing images with javascript. Before we go on tutorials there we explain some image functions on javascript.
1. onchange event
According to w3resource, The purpose of the HTML onchange attribute is to indicate to the user agent that the value of the element has changed. When the value of the element is changed, if the onchange attribute is used, a script is executed. HTML onchange attribute supports input, select, textarea elements.
2. createObjectURL
createObjectURL() The URL. createObjectURL() static method creates a DOMString containing a URL representing the object given in the parameter.