placeholder.html

var formPlaceholder = document.createElement("div");
<div id="tlh-form-placeholder" class="mobile-placeholder"></div>

vlh-forms_multiple-fix.js

var tlhForm = document.querySelector("#tlh-form");
var desktopFormParent = tlhForm.parentNode;
var mobileFormParent = document.getElementById("requestInfo")
var formPlaceholder = document.createElement("div");

// tlhForm.parentNode.removeChild(tlhForm);
formPlaceholder.setAttribute('id', 'tlh-form-placeholder');

function handleSmallerScreens() {
  desktopFormParent.replaceChild(formPlaceholder, tlhForm)
  mobileFormParent.replaceChild(tlhForm, formPlaceholder)
}

function handleLargerScreens() {
  mobileFormParent.replaceChild(formPlaceholder, tlhForm)
  desktopFormParent.replaceChild(tlhForm,formPlaceholder);
}

/* JavaScript Media Queries */
if (matchMedia) {
  const mq = window.matchMedia("(min-width: 500px)");
  mq.addListener(WidthChange);
  WidthChange(mq);
}

// media query change
function WidthChange(mq) {
  if (!mq.matches) {
  // On smaller screen size
    desktopFormParent.insertAdjacentElement("afterbegin", formPlaceholder)
    handleSmallerScreens()
    
  } else {
    console.log("move form to DESKTOP location");
    
    mobileFormParent.insertAdjacentElement("afterbegin", formPlaceholder)    
    handleLargerScreens()

  }
}

/* STEPS

- Declare variables for all elements that will be removed and added
- Remove desktop form
- Use replaceChild method to swap the form with the placeholder div
  with the form that was just removed
  
*/