regarding dynamic colour change

i am doing work on online examination system and from all of your support i have almost done my job but still there is a problem arising with me that when

i m going to direct link of question like tcs conducts in their exam programme then when the user already visited the question the question no colour is green but if the user is not visited the question the question colour is red so please buddies help me that how i can do this in my programme.

i will always thankful to all of u.