output标签，form表单 + <input type="range"> + output

<form oninput="x.value=parseInt(a.value)+parseInt(b.value)">
	0<input type="range" id="a" value="50">100
	+
	<input type="number" id="b" value="50">
	=
	<output name="x" for="a b"></output>
</form>

效果：