Coding to show Image depending on Time of day

I need some coding that shows an image and html text that says 'Online Now' depending on the time of day and day of the week. For example: Between 9am and 7pm Sydney Australia time Monday to Saturday I want it to show the text and image Online Now. All other times it is to show the text and image Offline. It is for a html page so will need to be js or if php need to have linked file etc. I want to be able to change the 9am-7pm times if I want. Any issues please just let me know.