因项目需要，封装一个查询localstorage占用了多少容量方

var sizeStore = 0;

if(window.localStorage) {

// 遍历所有存储

for(item in window.localStorage) {

if(window.localStorage.hasOwnProperty(item)) {

sizeStore += window.localStorage.getItem(item).length;

}

}

}

console.log((sizeStore / 1024 / 1024).toFixed(2) + 'M');