Write to CSV file locally with HTML5

Question

I was wondering whether HTML5 allows one to save/write to a local file within the user's file system. I'm asking this as I know that with HTML5 you can now export data from client and download it as a CSV file for example.

If not with HTML5, what would be the best approach to overwrite the contents, or create a CSV (or any other type of file for that matter) locally from within the client-side script?

You can create files through javascript (client-side). Here is an example of CSV creation: http://stackoverflow.com/questions/3286423/is-it-possible-to-use-any-html5-fanciness-to-export-local-storage-to-excel — Pedro Moreira, Nov 19 '14 at 10:06

score 11 · Accepted Answer · edited May 23 '17 at 12:13

Function:

function exportData() {
    var data = '';
    for (var i=1;i<=2;i++) {
        var sep = '';
        for (var j=1;j<=4;j++) {
            data +=  sep + document.getElementById(i + '_' + j).value;
            sep = ',';
        }
        data += '\r\n';
    }
    var exportLink = document.createElement('a');
    exportLink.setAttribute('href', 'data:text/csv;base64,' + window.btoa(data));
    exportLink.appendChild(document.createTextNode('test.csv'));
    document.getElementById('results').appendChild(exportLink);
}

Markup:

<input type="number" id="1_1" value="2">,
<input type="number" id="1_2" value="1">,
<input type="number" id="1_3" value="4">,
<input type="number" id="1_4" value="3">
<br>
<input type="number" id="2_1" value="1">,
<input type="number" id="2_2" value="2">,
<input type="number" id="2_3" value="3">,
<input type="number" id="2_4" value="4">
<br>
<button onclick="exportData()">Export as CSV</button>
<div id="results"></div>

Demo:

Click the button you get a link, click the link and you get a file. Change the values, click the link again and you get a different file. Firefox made me select Excel every time to open it but I don't know whether that's my configuration or a general issue.

Live Demo

Demo

Reference:

Is it possible to use any HTML5 fanciness to export local storage to Excel?

score 1 · Answer 2 · answered May 04 '18 at 14:00

I know this is a old question. Test ummahusla' answer it do works, but a small problem with the downloaded file, in my chrome it will download a no name file.

And after some testing here is the working code to download as csv file.

    data= 'data:application/csv;charset=utf-8,' + encodeURIComponent(data);
    var exportLink = document.createElement('a');
    exportLink.setAttribute('href', data);
    exportLink.setAttribute('download','test.csv');
    exportLink.setAttribute('target','_blank');
    exportLink.appendChild(document.createTextNode('test.csv'));

    document.getElementById('results').appendChild(exportLink);

Write to CSV file locally with HTML5

2 Answers2