site / test.js

function check(tab) {
    const tabs = tab.split('/')
    let path = 'tab'
    for (tab of tabs) {
        path = `${path}/${tab}`
        document.getElementById(path).checked = true
    }
}
function push(tab) {
    window.history.pushState(null, null, `?tab=${tab}`)
}
function update(id) {
    const tab = id.split('/').slice(1).join('/')
    push(tab)
}
function main() {
    let tab = (new URL(document.location)).searchParams.get('tab')
    if (tab) {
        check(tab)
    } else {
        tab = '1/1'
        check(tab)
        push(tab)
    }
}

function swap() {
    document.body.classList.toggle('dark')
}