Input parameter format

Hi,

 My script expects 2 inputs and one of them is supposed to be time, I would like to check if the given input is in validate format \(i.e. 16:00\), could anyone help me out here? thanks!

This is the prelim and u will have to look for tighter time checking ..but thats the start....
#! /bin/ksh
input=$1
echo $input
if [[ $input = [0-2][0-9]:[0-6][0-9] ]]
then
echo "Correct input"
else
echo "Incorrect input"
fi