revealPriceInDivar.js

function respHandler() {
    data = JSON.parse(this.responseText)
    price = data.data.webengage.price
    cells = document.getElementsByClassName('post-fields-item')
    last = cells[cells.length - 1]
    clone = last.cloneNode(true)
    clone.getElementsByTagName('span')[0].innerText = 'قیمت'
    clone.getElementsByTagName('div')[0].innerText = Number(price).toLocaleString()
    last.parentElement.appendChild(clone)
}

var req = new XMLHttpRequest()
req.addEventListener('load', respHandler)
url = window.location.href
id = url.substring(url.lastIndexOf('/') + 1)
req.open('GET', `https://api.divar.ir/v5/posts/${id}`)
req.send()