JSFiddle - React, Tailwind, and code Playground

HTML

<input type="file" id="fu" />
<input type="button" id="btn" value="Upload" />

JavaScript

$("#btn").click(function()
{    
    var fu = $("#fu");
    var ext = /[^.]+$/.exec(fu.val());
    if (ext!="rar")
    {
        fu.trigger("click");
    }
});