// JavaScript Document

function show_div(nid)	{
	
	turn = document.getElementById(nid);
	turn.style.visibility = "visible";

}


function hide_div(nid)	{
	
	turn = document.getElementById(nid);
	turn.style.visibility = "hidden";

}


<!-- Check all Script
function checkAll(obj)
{

var ss
var kk
kk= obj;

ss=document.form1.checkbox.checked;

if (ss == false)
{
	kk ="no";
	
}

// set the form to look at (your form is called form1)
var frm = document.form1
// get the form elements
var el = frm.elements
// loop through the elements...
for(i=0;i<el.length;i++) {
  // and check if it is a checkbox
  if(el[i].type == "checkbox" ) {
    // if it is a checkbox and you submitted yes to the function
    //alert(kk);
    if(kk == "yes")
      // tick the box
      el[i].checked = true;
    else
      // otherwise untick the box
      el[i].checked = false;
    }
  }
}