Prefer to use Number() rather than parseInt() - parseInt() is intended for conversion of numbers from one base to another. If you do
use parseInt() you ought to specify the radix (10).
You ask the user to enter numbers
, but then change them to integers
. Why can the user not enter 2.5, 3.7 and so on? And what if the user enters "XYZ" or something? You can trap NaN entries with
var box1 = Number(document.calculator.txtBox1.value) || 0; // assign 0 if the value entered is not a number.
box1 = parseInt(box1,10); // if you really do want integers. 10 is the radix (number base - i.e. decimal)
document.calculator.txtBox1.value = box1; // write it back to the field
Not sure what your document.write() is intended to output, but simply scrap it.