So you think you know all the CSS values and that only numbers are well.. numbers.
Well what if I told you that there is one number or should I say letter that you can enter in a number field and use in CSS values you would not expect. e is a trend setter because in CSS you can do this:
In html this will also work:
<input type='number' value='e'/>
Okay so before I explain.. I was once presented with a feedback form asking me to rate my experience between 1 and 10, I didn't think much of the form so I entered e, I'm not sure what the SQL database behind this thought of my helpful data, but there you go, you can't rely on client side validation.
Okay what is e all about? E or exponent is equivalent to pow() or power of. In my CSS example this notation gives a huge number 9 times 10 to the power of 9 (edit) and certainly larger than 9999px, so if you want to write less for your money's worth, e is the way to go.
Html number fields also count e as a number when no other letter will actually be typeable.
So that's e, a computed notation worth knowing.