JSFiddle - React, Tailwind, and code Playground

by not important

HTML

<div id="target"></div>

CoffeeScript

url = 'http://www.whatismyip.pw/'
formGroup = 'formAlpha'

iframe = document.createElement 'iframe'
iframe.id = 'formFrame'
iframe.width = 320
iframe.height = 480
iframe.src = 'google.com'

html = document.getElementsByTagName('body')[0]
html.appendChild iframe

iframeDoc = iframe.contentDocument
if !iframe.contentDocument.body
    iframe.contentDocument.body = iframe.createElement 'body'

form = iframeDoc.createElement 'form'
form.method = 'get'
form.action = url
form.id = formGroup
form.setAttribute 'submit', 'formSubmit()'

formElements = [
    {name: 'firstElement', value: 'firstValue'}
    {name: 'secondElement', value: 'secondValue'}
]

for {name, value} in formElements
    input = iframeDoc.createElement 'input'
    input.type = 'hidden'
    input.name = name
    input.value = value
    form.appendChild input

iframe.onload = ->
    console.log iframe.src

script = iframeDoc.createElement 'script'
script.innerHTML += "document.getElementById('#{formGroup}').submit();"

iframeDoc.getElementsByTagName('body')[0].appendChild form
iframeDoc.getElementsByTagName('body')[0].appendChild script