Тег <output></output>

Этот тег определяет результат расчета.

Аргумент	Значение
for	element_id
form	form_id
name	text

index.php

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>New Page</title>
</head>
<body>
<form oninput="x.value=parseFloat(a.value)+parseFloat(b.value)">
<fieldset>
<legend align="center">Sum of the two numbers</legend>
<br />
<input type="number" name="a" value="0">
   
<label>+</label>
   
<input type="number" name="b" value="0">
   
<label>=</label>
   
<output name="x" for="a b"></output>
<br />
<br />
<input type="reset" value="Clear" />
<br />
<br />
</fieldset>
</form>
</body>
</html>

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>New Page</title>
</head>
<body>
<form oninput="x.value=parseFloat(a.value)+parseFloat(b.value)">
<fieldset>
<legend align="center">Sum of the two numbers</legend>
<br />
<input type="number" name="a" value="0">
   
<label>+</label>
   
<input type="number" name="b" value="0">
   
<label>=</label>
   
<output name="x" for="a b"></output>
<br />
<br />
<input type="reset" value="Clear" />
<br />
<br />
</fieldset>
</form>
</body>
</html>