var l = document.getElementById("user_l");
var r = document.getElementById("user_r");
if(l && r)
{
    if(l.offsetHeight<r.offsetHeight)
    {
        l.style.height = (r.offsetHeight+10)+"px";
    }
    if(l.offsetHeight > r.offsetHeight)
    {
        r.style.height = (l.offsetHeight)+"px";
    }
}