function set_height()
{
    var a=document.getElementById("big_left")
    var b=document.getElementById("big_right")
    var c=document.getElementById("big_right_cart")
    var d
    if (a.scrollHeight<b.scrollHeight)     
    {
        d=b.scrollHeight;
    }
    else
    {
        d=a.scrollHeight;
    }
    if (d<c.scrollHeight)
    {
        d=c.scrollHeight;
    }
    else
    {
        d=d;
    }
    a.style.height=d+"px";
    b.style.height=d+"px";
    c.style.height=d+"px";
}