Scientific Calculator using HTML, CSS and Js
function backspace(calc){size=calc.display.value.length;calc.display.value=calc.display.value.substring(0,size-1);}
function calculate(calc){
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<=n;i++)
f=f*i;calc.display.value=f;}
else if(calc.display.value.includes("%")){size=calc.display.value.length;n=Number(calc.display.value.substring(0,size-1));calc.display.value=n/100;}
else
calc.display.value=eval(calc.display.value);}
 TEK Scientific Calculator