Looking for an image/html message display script according to hours of operation

[Tominator]

I am looking for a script that will either display html text or an image on my website according to the hours of operation that someone will be in the office to answer the phone if someone is prompted to call. Kind of like a store that would have an OPEN/CLOSED sign in their front window.

I want the message to either say in simple terms at this time:
"Call us, someone will answer the phone if you call"

or

"Call and leave a message if you have a question, our hours are 7AM-5PM, PST"

Does anyone have any recommendations for a good script that I can use for this purpose?

Thanks in advance! -Tom