JSFiddle - React, Tailwind, and code Playground
HTML
<input type="radio" name="radio" value="kai" checked> KAI
<input type="radio" name="radio" value="raillink"> RAILINK
<input type="submit" id="search-button" value="Cari tiket KAI">
JavaScript
$('input[name=radio]').click(function(){
var nilai = $(this).val();
$('#search-button').val("Cari tiket " + nilai.toUpperCase());
});
$('#search-button').click(function() {
var a = $('input[name=radio]:checked');
console.log(a, a.val());
if (a.val() === "kai") {
alert("kai");
} else {
alert("railink")
}
})