Form problem - invalid input

Question

iv been using the same code to make input forms ever since i
started but im having this recurring problem with one form. when
people fill in the form when they hit send, sometimes it sends and
other times it goes to a blank screen which says "invalid
input!".there is a line at the top of the php code which mentions
this and then refers to $field for which there is nothing in the
form called this.is that the problem? why would it only work
sometimes?
the line of code is this:
<?
function checkOK($field)
if (eregi("\r",$field) || eregi("\n",$field)){
die("Invalid Input!");
the code for the page can be found here:
http://www.mathminds.co.uk/tutor_application_form.html
thanks.

Answer 1

Greetings,
It appears that you are checking for carrige returns or newlines in the form fields.
Then calling die(); if one or the other is found.
Why not do some form validation to sanitize the input from your form fields correctly.
HTH
-Rb