function check()
  {
  if (document.getElementById("children").checked==true)
  	
  {
	  	  document.getElementById("children_num_container").style.visibility="visible";
		  document.getElementById("children_num").disabled=false;
  }
  else 
  {
	      document.getElementById("children_num").disabled=true;
		  document.getElementById("children_num_container").style.visibility="hidden";
  }
  }