Result Size: 331 x 419

<html>
<head>
<title>Scientific-Calculator</title>

</head>
<body>
  <script>
    function shiftFn(ken) {
    var shift = document.getElementById("shiftBtn") ;
    var arr = document.getElementsByTagName("td") ;
    if (ken == 1) {
        shift.setAttribute("onclick", "shiftFn(0)") ;
        shift.style.backgroundColor = "orange" ;
        arr[2].innerHTML = "sin<sup>-1</sup>" ;
        arr[2].setAttribute("onclick", "trigo1('sin')") ;
        arr[3].innerHTML = "cos<sup>-1</sup>" ;
        arr[3].setAttribute("onclick", "trigo1('cos')") ;
        arr[4].innerHTML = "tan<sup>-1</sup>" ;
        arr[4].setAttribute("onclick", "trigo1('tan')") ;
        arr[10].innerHTML = "ln" ;
        arr[10].setAttribute("onclick", "log(0)") ;
        arr[28].innerHTML = "\u0065" ;
        arr[28].setAttribute("onclick", "piOrE('e')") ;
    } else {
        shift.setAttribute("onclick", "shiftFn(1)") ;
        shift.style.backgroundColor = "yellow" ;
        arr[2].innerHTML = "sin" ;
        arr[2].setAttribute("onclick", "trigo('sin')") ;
        arr[3].innerHTML = "cos" ;
        arr[3].setAttribute("onclick", "trigo('cos')") ;
        arr[4].innerHTML = "tan" ;
        arr[4].setAttribute("onclick", "trigo('tan')") ;
        arr[10].innerHTML = "log" ;
        arr[10].setAttribute("onclick", "log(1)") ;
        arr[28].innerHTML = "\u03C0" ;
        arr[28].setAttribute("onclick", "piOrE('pi')") ;
    }
}

function input(sun) {
    var x = document.getElementById("result") ;
    var y = document.getElementById("myPara") ;
    x.value += sun ;
    y.innerHTML += sun ;
}

function factorial(shirious) {
    if (Number.isInteger(shirious)) {
        if (shirious < 2) return 1 ;
        return shirious * factorial(shirious - 1) ;
    }
}

function sqrt() {
    var x = document.getElementById("result") ;
    var y = document.getElementById("myPara") ;
    x.value += "sqrt(" ;
    y.innerHTML += (/[\d)IE]/.test(y.innerHTML.slice(-1))) ? 
    " * Math.sqrt(" : "Math.sqrt(" ;
}

function leftParen() {
    var x = document.getElementById("result") ;
    var y = document.getElementById("myPara") ;
    x.value += "(" ;
    y.innerHTML += (/[\d)IE]/.test(y.innerHTML.slice(-1))) ? 
    " * (" : "(" ;
}

function trigo(hatsyrei) {
    var x = document.getElementById("result") ;
    var y = document.getElementById("myPara") ;
    x.value += hatsyrei + "(" ;
    y.innerHTML += (/[\d)IE]/.test(y.innerHTML.slice(-1))) ? 
    " * Math." + hatsyrei + "(Math.PI / 180 * " : "Math." + hatsyrei + "(Math.PI / 180 * " ;
}

function trigo1(valentin) {
    var x = document.getElementById("result") ;
    var y = document.getElementById("myPara") ;
    x.value += valentin + "\u207B\u00B9("
    y.innerHTML += (/[\d)IE]/.test(y.innerHTML.slice(-1))) ? 
    " * 180 / Math.PI * Math.a" + valentin + "(" : "180 / Math.PI * Math.a" + valentin + "(" ;
}

function ac() {
    var x = document.getElementById("result") ;
    var y = document.getElementById("myPara") ;
    x.value = y.innerHTML = "" ;
}

function ans() {
    var x = document.getElementById("result") ;
    var y = document.getElementById("myPara") ;
    var z = document.getElementById("myAns") ;
    x.value += "Ans" ;
    y.innerHTML += (/[\d)IE]/.test(y.innerHTML.slice(-1))) ? 
    " * " + z.innerHTML : z.innerHTML ;
}