function adapt_size() {

 var h1 = document.getElementById("left_container").offsetHeight;

 var h2 = document.getElementById("menu").offsetHeight;

 var max = h1;

 if(h2 > max) max = h2;

 document.getElementById("left_container").style.height = max + "px";

 document.getElementById("menu").style.height = max + "px";

}