function chkcheckbox()
	{
		var frm = document.myform;
		for (var i=0;i<frm.elements.length;i++) 
		{
			var elmnt = frm.elements[i];
			if (elmnt.type=='checkbox') 
			{
				if(frm.chk_all.checked == true)
				{ 
					elmnt.checked=false; 
				}
				else
				{ 
					elmnt.checked=true; 
				}
			}
		}
		if(frm.chk_all.checked == true)
		{ 
			frm.chk_all.checked = false; 		
		}
		else
		{ 
			frm.chk_all.checked = true; 
		}
	}
	
function beforesubmit(actionbtn)
{
	var num = 0;
		var chkfrm = document.myform;
		for (var i=0;i<chkfrm.elements.length;i++) 
		{
			var elmnt = chkfrm.elements[i];
			if (elmnt.type=='checkbox') 
			{
				if(elmnt.checked == true)
				{
					num = num + 1;	
				}
			}
		}
	if(actionbtn == "delete")
	{
		if(num == 0 || num < 1)
		{
			alert("Please select Tour ID.");
			return false;
		}
	}
	else if(actionbtn == "edit")
	{
		if(num < 1)
		{
			alert("Please select Tour ID");
			return false;
		}
		else if(num > 1)
		{
			alert("Please select only one Tour ID");
			return false;
		}
	}
	return true;
}