Answers for "how validate radio button in javascript"

javascript check radio button

// Native JS solution:
document.getElementById("_1234").checked = true;
// JQuery solution:
$("#_1234").prop("checked", true);

javascript radio button value if checked

//alert(document.querySelector('input[name = "comp"]:checked').value);

$test=document.querySelector('input[name = "comp"]:checked').value;

if($test="silver") {
        amount=50;
    }else if($test="gold") {
      amount=90;
    }else{
      amount=30;
    }