Javascript change Div style

Question

I want that part 1 onclick div style changes and part 2 again on click it comes back to normal. I tried doing so but I failed to achieve the

Answer 1

A simple switch statement should do the trick:

function abc() {
    var elem=document.getElementById('test'),color;
    switch(elem.style.color) {
        case('red'):
            color='black';
            break;
        case('black'):
        default:
            color='red';
    }
    elem.style.color=color;
}