text field - numerical value

[novice2004]

Would you please provide me with some code that when entering something into text field accepts just numerical value (onKeyPress)
Thank you.


<TD><INPUT TYPE="text" NAME="Year_Of_Birth" maxLength="4"size="4"></TD>

 

[tviman]

Rather than create a function that detects each keypress, it's a little easier, and uses a lot less system resources, if you just validate the code before submission. The theory behind this is that you have to build a function that detects the keypress (or key release), calls the function to check if it's a numeric value, then return control back to the user. In many cases, a user can out type the function - type faster than the function can respond - and this can confuse the user when there are alert boxes popping up unexpectedly.

There's always a better way. The fun is trying to find it!

 

[tviman]

Forgot to add that such a function will fire even if the user catches the error and tries to correct it by using BACKSPACE to fix his/her error.

There's always a better way. The fun is trying to find it!

 

[AnanthaP]

isNaN() - or rather not isNan() - would do it.

You could also use parseInt() but be careful of leading zeros. If the first letter is a 0 (zero), parseInt() assumes the number to be an octal and so numbers with nine in them would be treated as invalid.

In your case since you want to vlidate only for years, you might write something like:

If length != 4 then error.
For i=0;i<4;i++
if (data < 0 || data > 9) then error; exit;
EndFor
Now validate for reasonableness of range.

HTH.
End