JSFiddle - React, Tailwind, and code Playground

by kougiland

HTML

<input type="file" id="files" name="files[]" multiple />
<output id="list"></output>

CSS

.thumb {
    height: 75px;
    border: 1px solid #000;
    margin: 10px 5px 0 0;
  }

JavaScript

// Check for the various File API support.
if (window.File && window.FileReader && window.FileList && window.Blob) {
    // Great success! All the File APIs are supported.
    alert('file api is supported');
} else {
    alert('The File APIs are not fully supported in this browser.');
}

function handleFileSelect(evt) {
    var files = evt.target.files; // FileList object
    // Loop through the FileList and render image files as thumbnails.
    for (var i = 0, f; f = files[i]; i++) {

        // Only process image files.
        if (!f.type.match('image.*')) {
            continue;
        }

        var reader = new FileReader();

        // Closure to capture the file information.
        reader.onload = (function(theFile) {
            return function(e) {
                // Render thumbnail.
                var span = document.createElement('span');
                span.innerHTML = ['<img class="thumb" src="', e.target.result,
                                                                                        '" title="', escape(theFile.name), '"/>'].join('');
                document.getElementById('list').insertBefore(span, null);
            };
        })(f);

        // Read in the image file as a data URL.
        reader.readAsDataURL(f);
    }
}

document.getElementById('files').addEventListener('change', handleFileSelect, false);