Open file in Javascript from user-specified file name

Question

I want to open a file in Javascript that the user selects from the local filesystem. I can get the file name but I don't know how to open it.

<form action='' method='POST' enctype='multipart/form-data'>
    <input id="archiveFile" type='file' name='userFile'><br>
    <script>
        archiveFile.onchange = function (e)
        {
            console.log(archiveFile.value);
            // open the file here
        }
    </script>
</form>

Answer 1

You need for the HTML5 FileReader Api, further information are there: https://developer.mozilla.org/en-US/docs/Web/API/FileReader

here is a polyfill using Flash: https://github.com/Jahdrien/FileReader

This is a very well-made article: http://www.html5rocks.com/en/tutorials/file/dndfiles/#toc-reading-files it explains almost everything.

working example:

 function FileReaderCtrl() { var self = this; var field = document.getElementById('fieldFile'); var result = document.getElementById('result'); self.readFile = function(event) { var res = event.target.result; var image = '<img src="'+ (res || '') +'"/>'; result.innerHTML = image; console.log(image); }; field.onchange = function(event) { var files = field.files; var reader; if(files.length < 1) { return; } reader = new FileReader(); reader.onload = self.readFile; reader.readAsDataURL(files[0]); } } document.addEventListener('DOMContentLoaded', FileReaderCtrl); 

 #result { width: 200px; height: 200px; background: lightcoral; margin: 1em auto; } img {max-width: 100% } 

 <label for="fieldFile">Select an Image:<br><input type="file" id="fieldFile"/></label> <div id="result"></div> 

Answer 2

Substitute archiveFile.files for archiveFile.value . The value of an input type="file" element is not a FileList or File object

For historical reasons, the value IDL attribute prefixes the file name with the string "C:\\fakepath\\"

archive.files would be the FileList object, from which you can iterate the selected File object or objects if multiple attribute is set at input type="file" element. For example, archiveFile.files[0] to view properties of individual File object

 <form action='' method='POST' enctype='multipart/form-data'> <input id="archiveFile" type='file' name='userFile'> <br> <script> archiveFile.onchange = function(e) { console.log(archiveFile.files, archiveFile.files[0]); // open the file here } </script> </form>