Preview an image before uploading it
We prepare the markup for a file input which allows to choose an image, and an img element for previewing the selected file.
<input type="file" id="fileInput" />
<img id="preview" />Both elements can be taken by the getElementById() method:
const fileEle = document.getElementById('fileInput');
const previewEle = document.getElementById('preview');1. Use the URL.createObjectURL() method
fileEle.addEventListener('change', function (e) {
// Get the selected file
const file = e.target.files[0];
// Create a new URL that references to the file
const url = URL.createObjectURL(file);
// Set the source for preview element
previewEle.src = url;
});2. Use the FileReader's readAsDataURL() method
fileEle.addEventListener('change', function (e) {
// Get the selected file
const file = e.target.files[0];
const reader = new FileReader();
reader.addEventListener('load', function () {
// Set the source for preview element
previewEle.src = reader.result;
});
reader.readAsDataURL(file);
});