function checkAll(form, field, list){
	var evaluate = document.getElementById(field).checked;
	var list_eval = document.form.list;
	 
	if(evaluate == true){
		for (i = 0; i < list_eval.length; i++){
			list_eval[i].checked = true ;
		}	
	}else{
		for (i = 0; i < list_eval.length; i++){
			list_eval[i].checked = false ;
		}
	}
}

function check_check_box(form, list){
	var list_eval = document.form.list;
	var flag = true;
	var count = 0;
	for (i = 0; i < list_eval.length; i++){
		if(list_eval[i].checked == true){
			count += 1;
			flag = false;
		}	 
	}
	
	if(flag){
		alert('Please select items to be downloaded');
		return false;
	}else {
		return true;
	}
}

function check1_check_box(items){
	var items_eval = document.getElementsByName(items);
	var flag = true;
	var count = 0;
	for (i = 0; i < items_eval.length; i++){
		if(items_eval[i].checked == true){
			count += 1;
			flag = false;
		}	 
	}
	
	if(flag){
		alert('Please select items first.');
		return false;
	}else {
		return true;
	}
}

function show(){
	var formobj = document.getElementById("theform");
	var toalert = "";
	var numchecked = 0;
	
	for(var i = 0 ; i < 20; i++){
		//toalert += "list["+ i +"]="+ formobj.elements['list['+ i +']'].checked + "\n";
		numchecked += formobj.elements['list['+ i +']'].checked ? 1 : 0;
	}
	toalert += "total checked: "+ numchecked;
	
	var thebox = document.getElementById("echo");
	thebox.innerHTML = toalert;
	//alert(toalert);
}

function check(chk){
	if(document.getElementById('form').check_all.value=="Check All"){
		for (i = 0; i < chk.length; i++)
			chk[i].checked = true ;
			document.getElementById('form').check_all.value="Uncheck All";
	}else{
		for (i = 0; i < chk.length; i++)
			chk[i].checked = false ;
			document.getElementById('form').check_all.value="Check All";
	}
}