JSFiddle - React, Tailwind, and code Playground

by Lexogram

HTML

<div id='InformationDiv'>

         <fieldset id='fieldset1'>
              To be replaced             
         </fieldset>

         <div id='fixDiv'>
             This
             must
             remain
         </div>

         <fieldset id='fieldset2'>
              Replace this                
         </fieldset>
      </div>

JavaScript

setTimeout(function() {
      replace();
    }, 1000);

    function replace() {
      var fieldsets = document.getElementsByTagName('fieldset');
      var fieldset;
      var parent = fieldsets[0].parentNode;
  
      // Create the replacement material
      var newStuff = [];
      var p = document.createElement('p');
      p.innerHTML = 'This is new';
      newStuff.push(p);
      p = document.createElement('p');
      p.innerHTML = 'This is also new';
      newStuff.push(p);
  
      // Replace
      for (var ii=fieldsets.length;ii>0;) {
        ii--;
        fieldset = fieldsets[ii];
        parent.replaceChild(newStuff[ii], fieldset);
      }
    }