<!DOCTYPE html>
<html>
<head>
	<title>Basic Calculator</title>
    <script language="javascript">
		function cal()
		{
			var n1,n2,res,opr;
			n1=parseInt(document.getElementById("t1").value);
			n2=parseInt(document.getElementById("t2").value);
			opr=document.getElementById("s1").value;
			switch(opr)
			{
				case '+':
				res=n1+n2;
				document.getElementById("t3").value=res;
				break;
				case '-':
				res=n1-n2;
				document.getElementById("t3").value=res;
				break;
				case '*':
				res=n1*n2;
				document.getElementById("t3").value=res;
				break;
				case '/':
				res=n1/n2;
				document.getElementById("t3").value=res;
				break;
				default:
				document.getElementById("t3").value="Invalid Operator";
			}
		}
	</script>
</head>

<body>
	<form>
    	<table>
        	<tr>	
            	<td>Number 1</td>
                <td><input type="number" id="t1"/></td>
            </tr>
            <tr>	
            	<td>Number 2</td>
                <td><input type="number" id="t2"/></td>
            </tr>
            <tr>	
            	<td>Result</td>
                <td><input type="text" id="t3"/></td>
            </tr>
            <tr>	
            	<td>Select Operation</td>
                <td>
                	<select id="s1">
                    	<option value="">Select Operation</option>
						<option value="+">Addition</option>
                        <option value="-">Substraction</option>
                        <option value="*">Product</option>
                        <option value="/">Quotient</option>
                    </select>
                </td>
            </tr>
            <tr>	
            	<td></td>
                <td><input type="button" value="Calculate" onClick="cal()"/></td>
            </tr>
        </table>
    </form>
</body>
</html>

xxxxxxxxxx
                <td><input type="button" value="Calculate" onClick="cal()"/></td>
 
<!DOCTYPE html>
<html>
<head>
    <title>Basic Calculator</title>
    <script language="javascript">
        function cal()
        {
            var n1,n2,res,opr;
            n1=parseInt(document.getElementById("t1").value);
            n2=parseInt(document.getElementById("t2").value);
            opr=document.getElementById("s1").value;
            switch(opr)
            {
                case '+':
                res=n1+n2;
                document.getElementById("t3").value=res;
                break;
                case '-':
                res=n1-n2;
                document.getElementById("t3").value=res;
                break;
                case '*':
                res=n1*n2;
                document.getElementById("t3").value=res;
                break;

​x
 
​

​

O Level Exam : Practical Question

🖥 Output: