Special Code

<script>

function cal(){

var a =parseInt(document.getElementById('t5').value);

var b =parseInt(document.getElementById('t6').value);

var c = a * b;

parseInt(document.getElementById('t7').value = c);

}

var form=document.getElementById("formId");

function submitForm(event){

//Preventing page refresh

event.preventDefault();

}

//Calling a function during form submission.

form.addEventListener('submit', submitForm);

</script>

<form action="#" method="post" enctype="multipart/form-data">

    <meta charset="UTF-8">

    <meta http-equiv="X-UA-Compatible" content="IE=edge">

    <meta name="viewport" content="width=device-width, initial-scale=1.0">  

    <link rel="stylesheet" href="style.css">  

<form action="" method="POST" enctype="multipart/form-data">


function closeForm1() {

document.getElementById("myForm").style.display = "none";

}

<body><center>

<input type="text" id="txt" name="txt" placeholder="ຈໍານວນນັກສຶກສາ" /><br><br>

<button onclick="getVal();"> ເລືອກຜູ້ໂຊກດີ </button><br><br>

<input type="text" id="txt1" name="txt" placeholder="ຜູ້ຖາມ" /><br>

<input type="text" id="txt2" name="txt" placeholder="ຜູ້ຕອບ" /><br>

<br></center>

<script>

document.getElementById('txt').Value="";

function getVal(){

var txt = parseInt(document.getElementById('txt').value);

var R = parseInt(Math.random() * txt + 1);

var R2 = parseInt(Math.random() * txt + 1);

//alert(R);

    document.getElementById('txt1').value = R;

document.getElementById('txt2').value = R2;

}

</script>

<script async src="https://drv.tw/inc/wd.js"></script>

</body>