function removeModel() {

	var list = document.getElementsByName('list');

	var c = "0";
	var url = "";
	for (var i = 0; i < list.length; ++i) {
		if (list[i].type == 'checkbox' && list[i].checked == true) {
			url = url + "&remove["+c+"]="+ document.getElementsByName('list')[i].value;
			c=eval(c+1);
		}
	}
	if(url != "") {
		window.top.location.href = "checkout.php?remove_model=true&"+url;
	}
}

function addModel(id_model) {
	var hours;
	hours = document.getElementById("hours_"+id_model).value;
	window.top.location.href = "checkout.php?id_model="+id_model+">&qtde=1&add_model=1&hours="+hours;
}