JS获取localstorage已使用容量⁄大小。

function getUseSize() {
    var size = 0;
    for (item in window.localStorage) {
        if (window.localStorage.hasOwnProperty(item)) {
            size += window.localStorage.getItem(item).length;
        }
    }
    console.log('使用：' + (size / 1024).toFixed(2) + 'KB')
}

getUseSize();