JSFiddle - React, Tailwind, and code Playground
JavaScript
var data='col1,col2\nval1,val2';
var a = document.createElement('a');
a.href = 'data:application/csv;charset=utf-8,' + encodeURIComponent(data);
//supported by chrome 14+ and firefox 20+
a.download = 'data.csv';
//needed for firefox
document.getElementsByTagName('body')[0].appendChild(a);
//supported by chrome 20+ and firefox 5+
a.click();