function handle_checkboxes() {
	var elem = document.cnl_form.elements;
	
	for(var i = 0; i < elem.length; i++) {
		if(elem[i].type == "checkbox") {
			if(this.id == "select_btn") {
				elem[i].checked = true;
			} else if(this.id == "reset_btn") {
				elem[i].checked = false;
			}
		}
	}	
}
if(window.addEventListener) {
	window.addEventListener("load", function() {
		document.getElementById('select_btn').addEventListener("click", handle_checkboxes, false);
		document.getElementById('reset_btn').addEventListener("click", handle_checkboxes, false);
	}, false);
} else if(window.attachEvent) {
	window.attachEvent("onload", function() {
		// using traditional method of assigning event handler
		// because you can't pass 'this' using attachEvent, and
		// our 'handle_checkboxes' function relies on 'this' to 
		// know whether or not 'checked' should be true or false
		document.getElementById('select_btn').onclick = handle_checkboxes;
		document.getElementById('reset_btn').onclick = handle_checkboxes;
	});
}