calculate discount

HTML

<s>calculate discount</s>
<form name="discountCalculator" >
    <input type="text" name="price" >
    <input type="text" name="discount" > = 
    <input type="text" name="afterDiscount" >
</form>
<input type="button" value="submit" onclick="calculate()">

JavaScript

function calculate() {
   var price=0, discount=10, afterDiscount=0;
    price = Number(document.discountCalculator.price.value);
    discount = Number(document.discountCalculator.discount.value);


 afterDiscount=price - ( price*discount/100 );

   document.discountCalculator.price.value=price.toFixed(2);
   document.discountCalculator.discount.value=discount.toFixed(2);
   document.discountCalculator.afterDiscount.value=afterDiscount.toFixed(2);

}