HTML / calculator

Scientific Calculator using HTML, CSS and Js /* Style to set the title of calculator */ .title { margin-bottom: 10px; padding: 5px 0; font-size: 20px; font-weight:bold; text-align:center; width: 800px; color:blue; border: solid black 2px; } /* Set the button style */ #btn { width: 100%; height: 80px; font-size: 80px; } input[type="button"] { background-color:blue; color: black; border: solid black 2px; width:100% } /* Set input textarea */ input[type="text"] { background-color:white; border: solid black 2px; width:100% } /* Creating function in HTML for backspace operation */ function backspace(calc) { size = calc.display.value.length; calc.display.value = calc.display.value.substring(0, size-1); } /* Creating function to calculate factorial of element */ function calculate(calc) { /* Check if function include ! character then calculate factorial of number */ if(calc.display.value.includes("!")) { size = calc.display.value.length; n = Number(calc.display.value.substring(0, size-1)); f = 1; for(i = 2; i