2 divs in a larger div must equal the same height… but how?

Question

So here is a picture:

What the problem is that I have 2 divs in a cont

Answer 1

HTML

    
First Div content goes here
    
Second Div content goes here

CSS

.wrapper {
        width: 960px;
        overflow: hidden;
        margin: 0px auto;
    }

    .child_1, .child_2 {
        padding-bottom: 9999em;
        margin-bottom: -9999em;
        width: 50%;
        float: left;
    }

    .child_1 {
        background: #f00;
    }

    .child_2 {
        background: #0f0;
    }