JSFiddle - React, Tailwind, and code Playground

HTML

<div id="calc">
	<input type="text" id="one" class="form-control">
	<input type="text" id="two" class="form-control">
	
	<button type="button" id="plus" class="btn btn-success">+</button>
	<button type="button" id="minus" class="btn btn-warning">-</button>
	<button type="button" id="multiply" class="btn btn-danger">*</button>
	<button type="button" id="divide" class="btn btn-primary">/</button>
</div>

JavaScript

window.onload = function () {
	var one, two, plus, minus, multiply, divide, result, plusFnc, minusFnc;
	plus  	 = document.getElementById('plus');
	minus 	 = document.getElementById('minus');
	multiply = document.getElementById('multiply');
	divide   = document.getElementById('divide');


	function values () {
		one = Number(document.getElementById('one').value);
		two = Number(document.getElementById('two').value);
	}




var Calculate = function () {
	values();
	alert('наш результат ' + result);
}


Calculate.prototype.plusFnc = function () {
	result = one + two;
};

Calculate.prototype.minusFnc = function () {
	result = one - two;
};

Calculate.prototype.multiplyFnc = function () {
	result = one * two;
};

Calculate.prototype.divideFnc = function () {
	result = one / two;
};





/*
	function plusFnc () {
		values();
		result = one + two;
		alert('наш результат ' + result);
	}

	function minusFnc () {
		values();
		result = one - two;
		alert('наш результат ' + result);
	}

	function multiplyFnc () {
		values();
		result = one * two;
		alert('наш результат ' + result);
	}


	function divideFnc () {
		values();
		result = one / two;
		alert('наш результат ' + result);
	}

	*/

/*
	plus.onclick = function () {
		plusFnc();
	};

	minus.onclick = function () {
		minusFnc();
	};

	multiply.onclick = function () {
		multiplyFnc();
	};

	divide.onclick = function () {
		divideFnc();
	};
*/
};