// Defining some global variables

    var result = 0;
    var result_sq = 0;
    var final;
    var operation;  

    // Here we get the input id's

    add = document.getElementById('add');
    substract = document.getElementById('substract');
    multiply = document.getElementById('multiply');
    divide = document.getElementById('divide');
    square = document.getElementById('square');
    square_root = document.getElementById('square_root');

    // When the button with the Id is clicked the according function is called

    add.onclick =function add(e){
        e.preventDefault();
        A = document.getElementById('A').value;
        console.log(A);
        B = document.getElementById('B').value;
        console.log(B);
        var result = (A*1 + B*1);                   // I multiply it by 1 because .js sometimes thinks nuber is a string
        operation = "+";                            // I use a String to store the mathematical operation
        write_result_basic(result);                 // Here I call the function, which will display the result
    }
    substract.onclick = function(e){
        e.preventDefault();
        A = document.getElementById('A').value;
        B = document.getElementById('B').value;
        var result = (A*1 - B*1);
        operation = "-";
        write_result_basic(result);
    }
    multiply.onclick = function(e){
        e.preventDefault();
        A = document.getElementById('A').value;
        B = document.getElementById('B').value;
        var result = (A*1 * B*1);
        operation = "*";
        write_result_basic(result);
    }
    divide.onclick = function(e){
        e.preventDefault();
        A = document.getElementById('A').value;
        B = document.getElementById('B').value;
        var result = (A*1 / B*1);
        operation = "/";
        write_result_basic(result);
    }
    square.onclick = function(e){
        e.preventDefault();
        C = document.getElementById('C').value;
        sq = document.getElementById('sq').value;
        var result_sq = Math.pow(C,sq);
        write_result_sq(result_sq,sq);
    }
    square_root.onclick = function(e){
        e.preventDefault();
        C = document.getElementById('C').value;
        var result_sq_root = Math.sqrt(C);
        write_result_sq_root(result_sq_root);
    }
    function write_result_basic(res){
        document.getElementById('result').innerHTML = "The result of A " + operation + " B is: " + res;   // Here we display the results under the form
    }
    function write_result_sq(res2,sq){
        document.getElementById('result_sq').innerHTML = "The result of C to the power of " + sq +" is: " + res2;
    }
    function write_result_sq_root(res3){
        document.getElementById('result_sq').innerHTML = "The square root of C is: " + res3;
    }