Create a file using Javascript in Chrome on client side

Question

I would like to know if I can create a text file and save the file in the users "Downloads" section in his/her computer using Javascript. The way my feature should work is when the user clicks the submit button, I populate the users info in the text file and then save it in his machine. I would like this to work in Google Chrome.

Is this possible? I have seen posts that specifically tell me that it is a serious security issue.

Solution 1

Sure you can, using the brand new APIs.

 window.requestFileSystem = window.requestFileSystem || window.webkitRequestFileSystem;

 window.requestFileSystem(window.TEMPORARY, 1024*1024, function(fs) {
    fs.root.getFile('test.bin', {create: true}, function(fileEntry) { // test.bin is filename
        fileEntry.createWriter(function(fileWriter) {
            var arr = new Uint8Array(3); // data length

            arr[0] = 97; // byte data; these are codes for 'abc'
            arr[1] = 98;
            arr[2] = 99;

            var blob = new Blob([arr]);

            fileWriter.addEventListener("writeend", function() {
                // navigate to file, will download
                location.href = fileEntry.toURL();
            }, false);

            fileWriter.write(blob);
        }, function() {});
    }, function() {});
}, function() {});

Solution 2

Enter this into the Chrome browser

data:text;charset=utf-8,helloWorld

So to construct the download for your users you would do something like

data='<a href='data:text;charset=utf-8,'+uriEncode(yourUSERdataToDownload)+' >Your Download</a>

Then inject it into the dom for your user to press.

Solution 3

The following method works in IE11+, Firefox 25+ and Chrome 30+:

<a id="export" class="myButton" download="" href="#">export</a>
<script>
    function createDownloadLink(anchorSelector, str, fileName){
        if(window.navigator.msSaveOrOpenBlob) {
            var fileData = [str];
            blobObject = new Blob(fileData);
            $(anchorSelector).click(function(){
                window.navigator.msSaveOrOpenBlob(blobObject, fileName);
            });
        } else {
            var url = "data:text/plain;charset=utf-8," + encodeURIComponent(str);
            $(anchorSelector).attr("download", fileName);               
            $(anchorSelector).attr("href", url);
        }
    }

    $(function () {
        var str = "hi,file";
        createDownloadLink("#export",str,"file.txt");
    });

</script>

See this in Action: http://jsfiddle.net/Kg7eA/

Firefox and Chrome support data URI for navigation, which allows us to create files by navigating to a data URI, while IE doesn't support it for security purposes.

On the other hand, IE has API for saving a blob, which can be used to create and download files.

Solution 4

Try this:

document.body.innerHTML+="<a id='test' href='data:text;charset=utf-8,"+encodeURIComponent("hi")+"'>Your Download</a>";
document.getElementById('test').click();

if you want to set the filename use download attribute of anchor tag:

document.body.innerHTML+="<a id='test' href='data:text;charset=utf-8,"+encodeURIComponent("hi")+"' download=yourfilename>Your Download</a>";
document.getElementById('test').click();

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