Script that validates 3 inputs

This is what I have. I am trying to validate 3 inputs. The first and the second inputs do not ask me to enter the correct input. What is wrong? #!/bin/bash while : do echo "Please enter your tittle:" read TITTLE echo "Please enter your surname:" read SURNAME echo "Please enter your ID No." read ID if [ "$TITTLE" = "" ] || [ "${TITTLE//[!0-9]}" != "" ]; then echo "Enter your valid tittle without special characters." echo "Please try again." exit 1 fi if [ "$SURNAME" = "" ] || [ "${SURNAME//[!0-9]}" != "" ]; then echo "Enter your valid surname without special characters." echo "Please try again." exit 1 fi if [ "$ID" = "" ] || [ "${ID//[0-9]}" != "" ]; then echo "Enter your valid ID No. without special characters." echo "Please try again" else echo "Thank you" $TITTLE $SURNAME break fi done