JSFiddle - React, Tailwind, and code Playground

by David Thomas

HTML

<form action="#" method="post" id="theForm">
    <fieldset id="start">
        <input>
        <input>
        <input>
        <input>
        <input>
    </fieldset>
    <a href="#" id="aElement">Add more fields</a>
</form>

JavaScript

function addInput(insertAt, formEl, num, inputType, defaultVal) {
    console.log(formEl);
    if (!formEl) {
        return false;
    }
    else {
        num = num ? num : 5;
        var fieldset = document.createElement('fieldset'),
            newInput;
        for (var i = 0; i < num; i++) {
            newInput = document.createElement('input');
            newInput.value = defaultVal || '';
            newInput.type = inputType || 'text';
            fieldset.appendChild(newInput);
        }
        formEl.insertBefore(fieldset, insertAt);
    }
}

var formEl = document.getElementById('theForm'),
    aElem = document.getElementById('aElement');

if (window.addEventListener) {
    // up to date browsers
    aElement.addEventListener('click', function() {
        addInput(this, formEl, 10);
    }, false);
} else if (window.attachEvent) {
    // legacy IE, <9
    aElement.attachEvent('onclick', function() {
        addInput(this, formEl);
    });
}