How can I reference a cell in a custom function while setting up data validation in Google spreadsheets?

Question

I made the following Google script to check whether a string is less than some length:

function isLengthLessThan(length, text) {
  return (text.length < length)
};

How can I set up data validation using this custom formula to check the length of cells? What can I put where the question mark is so that it will represent the value of the cell?

Answer 1

Please try:

=len(A1)>9  

applied to a range starting with A1.