How to make a letter eraser?

Question

I've finally made a big, draggable calculator that can calculate *,/,+,-,square root and PI. (And use parantheses).

I got a reset button but I need an erase button that only deletes one letter. How do you make that?

I've tried this:

function BackSpace()
{
cal.in.value-=" ";
}

But it doesn't work and the input field just displays NaN.

For the reset button I use:

function Reset()
{
cal.in.value+=" ";
}.

I use similar functions for all other inputs. But I need a way to delete a single letter.

Answer 1

Found the answer.

I did something weird and now it works.

Answer 2

care to share the working code?

Answer 3

sure.

function BackSpace()
{
cal.in.value = (cal.in.value).slice(0, -1);

if(cal.in.value == ' ')
{
para.innerHTML = ' ';

cal.in.value="0";
}
}

Answer 4

Its nice to see people as passionate as you