JSFiddle - React, Tailwind, and code Playground

HTML

<select id="select_seasons">
        <option value="1">1</option>
        <option value="2">2</option>
        <option value="3">3</option>
        <option value="4">4</option>
</select>
<div id="container"></div>

JavaScript

document.getElementById('select_seasons').addEventListener('change', function(){ 
    var container = document.getElementById('container');
    
    container.innerHTML = ''; //clear
    
    //Find selected option
    var n = 1;
    for(var i = 0; i < this.options.length; ++i){
        if(this.options[i].selected){
            n = ~~this.options[i].value; //Cast to int
            break;
        }
    }
    
    for(var i = 1; i <= n; ++i){ //Because we want to count from 1 not 0
        var newDiv = document.createElement('div'); 
        newDiv.id = 'element-' + i; 
        newDiv.innerHTML = "<label>Episode " + i + " name</label> <input type='text' name='episode[" + i +"]' /> <label>Episode " + i + " embed</label> <input type='text' /> ";

        container.appendChild(newDiv);
    }
}); 

//Emit event on page init
document.getElementById('select_seasons').dispatchEvent(new Event('change'));