function Calculator(id) {
    var moduleNode = document.getElementById(id);
    var textBox = moduleNode.getElementsByClassName("textBox")[0];
    calc = function(e) {
        val = e.target.value;
        if (e.target.type != "button") {
            return;
        }
        if (val != "=") {
            textBox.value += val;
        } else {
            textBox.value = eval(textBox.value)
        }
    }

    moduleNode.onclick = calc;
}

new Calculator("xyz");
new Calculator("xyz1");

Setting Validate Copy Format

.textBox {
  text-align:right;
}
div{
  float:left;
  margin:0 15px;
}

Setting Validate Copy Format

<div id="xyz">
  <input type="text" class="textBox" size="20"/><br/>
  <input type="button" value="1" />
  <input type="button" value="2" />
  <input type="button" value="3" />
  <input type="button" value="4" /><br>
  <input type="button" value="5" />
  <input type="button" value="6" />
  <input type="button" value="7" />
  <input type="button" value="8" /><br>
  <input type="button" value="9" />
  <input type="button" value="0" />&nbsp;&nbsp;&nbsp;
  <input type="button" value="=" /><br>
  <input type="button" value="+" />
  <input type="button" value="-" />
  <input type="button" value="%" />
  <input type="button" value="/" />
</div>

<div id="xyz1">
  <input type="text" class="textBox" size="20"/><br/>
  <input type="button" value="1" />
  <input type="button" value="2" />
  <input type="button" value="3" />
  <input type="button" value="4" /><br>
  <input type="button" value="5" />
  <input type="button" value="6" />
  <input type="button" value="7" />
  <input type="button" value="8" /><br>
  <input type="button" value="9" />
  <input type="button" value="0" />&nbsp;&nbsp;&nbsp;
  <input type="button" value="=" /><br>
  <input type="button" value="+" />
  <input type="button" value="-" />
  <input type="button" value="%" />
  <input type="button" value="/" />
</div>

Copy Format

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