How to use in javascript information written in teg <input type = 'text' >

<div id="content"> 
<form name="calc" class="wrapper"> 
  <input type="text" name="input" class="display"> 
  <div class="buttons" name="input"> 
    <input type="button" value="1" OnClick="calc.input.value += '1'"> 
	<input type="button" value="2" OnClick="calc.input.value += '2'"> 
	<input type="button" value="3" OnClick="calc.input.value += '3'"> 
	<input type="button" value="4" OnClick="calc.input.value += '4'"> 
	<input type="button" value="+" OnClick="calc.input.value += '+'"> 
  </div> 
  <div class="buttons" name="input"> 
     
	<input type="button" value="5" OnClick="calc.input.value += '5'"> 
	<input type="button" value="6" OnClick="calc.input.value += '6'"> 
	<input type="button" value="7" OnClick="calc.input.value += '7'"> 
	<input type="button" value="8" OnClick="calc.input.value += '8'"> 
	<input type="button" value="-" OnClick="calc.input.value += '-'"> 
  </div> 
  <div class="buttons" name="input"> 
 
	<input type="button" value="9" OnClick="calc.input.value += '9'"> 
	<input type="button" value="0" OnClick="calc.input.value += '0'"> 
	<input type="button" value="." OnClick="calc.input.value += '.'"> 
	<input type="button" value="√" OnClick="calc.input.value = eval(Math.sqrt(calc.input.value))"> 
	<input type="button" value="X" OnClick="calc.input.value += '*'"> 
  </div> 
    <div class="buttons" name="input"> 
	<input class="res" type="button" value="=" OnClick="calc.input.value = eval(calc.input.value)"> 
    <input type="reset" value="C" OnClick="calc.input.value += ''"> 
	<input type="button" value="X²" OnClick="calc.input.value = eval(Math.pow(calc.input.value,2))"> 
	<input type="button" value="/" OnClick="calc.input.value += '/'"> 
  </div> 
</form> 
</div>

var num1 = document.getElementById('num1'), 
    num2 = document.getElementById('num2'); 
 
function doSomething() { 
    console.log(num1.value + ',' + num2.value); 
}

 <input id="num1" type="number"/><br> 
 <input id="num2" type="number"/><br> 
 <button onclick="doSomething();" type="submit"> 
 Submit 
 </button>