js交换两个div的位置

function exchange(el1, el2){
        var ep1 = el1.parentNode,
            ep2 = el2.parentNode,
            index1 = Array.prototype.indexOf.call(ep1.children, el1),
            index2 = Array.prototype.indexOf.call(ep2.children, el2);
        ep2.insertBefore(el1,ep2.children[index2]);
        ep1.insertBefore(el2,ep1.children[index1]);
    }