input file 미리보기 이미지

const inputImage = document.getElementById("category_image");
inputImage.addEventListener("change", e => {
    readImage(e.target);
});

function readImage(i) {

    if(i.files && i.files[0]) {
        const reader = new FileReader();

        reader.onload = e => {
            let previewImage = $('.img_box');
            previewImage.attr("src", e.target.result);
        }

        reader.readAsDataURL(i.files[0]);
    }

}


<input type="file" id="category_image">
<img class="img_box" />