JSFiddle - React, Tailwind, and code Playground

HTML

<input id="txt1" type="textbox" />
<input id="txt2" type="textbox" />
<input id="txt3" type="textbox" />
<input type="button" ID="btnCheck" value="check" />

JavaScript

$('#btnCheck').click(function() {
    if ($('#txt1').val().length > 0) {
        var txt2Val = $('#txt2').val().length,
            txt3Val = $('#txt3').val().length;            
        if( txt2Val == 0 || txt3Val == 0) {
            alert('Missing Value');   
        }
    }
});