CSS:using single rule for multiple Ids

Question

I was using a generic rule for TH tag of Table but it disturbed every thing. I was using the rule as:

th
{
    color: #fff;
    background: #7d7e7d;
}

But now I want to specify Ids for a few tables so that it does not effect other tables at all. What I did was:

#id1,#id2  th
{
    color: #fff;
    background: #7d7e7d;
}

what it did that color spread in as well. How do I achieve my task?

Answer 1

You need to specify th both times as the comma separates entire selectors:

#id1 th, #id2 th
{
    color: #fff;
    background: #7d7e7d;
}

Otherwise you're selecting the entire #id1 as well as just #id2 th.