Input displays the currently selected picture

1.jsp Code

<div class="lf salebd">
    <a href="#">
        <img src="images/ad20.jpg" id="img" width="100" height="100"/></a></div>

2.js Code

 $(function () {
            $("#file").change(function () {
                if (this.files.length) {
                    let file = this.files[0];
                    let reader = new FileReader();
                    // newly build  FileReader  object 
                    reader.onload = function () {
                        //  When  FileReader  When reading a file , The read results will be placed in  FileReader.result  Properties of the 
                        document.querySelector('#img').src = this.result;
                        document.querySelector('#text').innerHTML = this.result;
                    };
                    //  Set how to read files , Here we use base64 The way 
                    reader.readAsDataURL(file);
                }
            })
        })

3. effect