Как починить сложение?

var p1= 10;
var p2 = 100;
var p3 = 500;
var p4= 1000;
var s = false;
var score = 0;
var bonus = 0;
var loading = true;
function pre_load() {
	document.getElementById('xy').innerHTML = "XY: " + score;
	alert(score);
	alert(bonus);
	
}
function save() {
	if(localStorage) {
		localStorage.setItem('score', score);
		localStorage.setItem('bonus', bonus);
	}
}

function load() {
  if(loading = true) {
	if(localStorage) {
		
		if(localStorage.getItem('score') > 0) {
	score = localStorage.getItem('score');
} 

else {score = 0;}
	
	if (localStorage.getItem('bonus') > 0) 
		{bonus = localStorage.getItem('bonus');} 
		
		else {
		bonus = 1;
		save();}
		}
pre_load();
}
}

function click_main() {
	score = score + bonus;
	save();
	document.getElementById('xy').innerHTML('id');

function Magaz() {
var val = document.getElementById('mag').value;
var object = document.getElementById('shop');
if (val == "Открыть") {
	document.getElementById('mag').value = "Закрыть";
	object.style.display == 'block' ? object.style.display = 'none' : object.style.display = 'block';
} 
if (val == "Закрыть") {
	document.getElementById('mag').value = "Открыть";
	object.style.display == 'none' ? object.style.display = 'block' : object.style.display = 'none';
} 
}