▶ document.getElementById().value > SCRIPT

<h3>숫자1, 숫자2 값을 입력후 확인 버튼을 클릭해 보자</h3>

<script type="text/javascript">

function sum(){

num1 = document.getElementById("x").value;

num2 = document.getElementById("y").value;

alert(num1);

alert(num2);

sum3 = parseInt(num1) + parseInt(num2);

document.getElementById("z").value=sum3;

}

</script>

숫자1 : <input id="x" value=""><br>

숫자2 : <input id="y" value=""><br>

합계 : <input id="z" value="">

<input type="button" value="확인" onclick="sum()">