That code is saying that when you leave the '#CAT_Custom_194495' field, that its value should be checked, and a different field called '#weburl' should be coloured depending on the validity of the '#CAT_Custom_194495' field. I'm not sure if that's what you intend the code to do or not.
What is the HTML form code that the script is being used with?
Also, why is $input there? It doesn't appear to be used by anything.