使用 javascript 向 html 正文添加评论和回复按钮

Question

I want to add html elements to the body of my page as an unordered list. I have used DocumentFragment method to create a fragment of the reply button and comment span . Now I need to add a textbox and a add reply to that ul whenever a user clicks on the reply button and add all the replies as a list next to respective comment. Here is what I've tried:

 function comment() { var my_comment = document.getElementById('comments'); my_comment.innerHTML = "<textarea id='user_comment'> </textarea> <button onclick='addNewItem()'>Post Comment</button>"; } function addNewItem() { var thediv = document.getElementById("comments_and_replies"); var listItem = document.createElement("ul"); var replyBox = document.createElement("textbox"); var commentSpan = document.createElement("span"); var user_comment = document.getElementById('user_comment'); var replyButton = document.createElement("button"); listItem.className = "comments-list"; replyButton.innerText = "Reply"; replyButton.className = "reply"; replyButton.addEventListener("click", function() { var g = document.getElementById('comments_and_replies'); for (var i = 0, len = g.children.length; i < len; i++) { (function(index) { g.children[i].onclick = function() { listItem.insertBefore(replyBox, listItem.children[index]); } })(i); } }) commentSpan.textContent = user_comment.value; var documentFragment = document.createDocumentFragment(); documentFragment.appendChild(listItem); listItem.appendChild(commentSpan); listItem.appendChild(replyButton); thediv.appendChild(documentFragment); }

 <section><button onclick="comment()">Leave a comment</button></section> <div id="comments"></div> <div id="comments_and_replies"></div>

Answer 1

Event delegation on a single <form> can accommodate an unlimited amount of <button> s even if they are added after the page has loaded.

The example below uses the following:

• document.forms
• .elements
• event.currentTarget
• event.target
• .matches()
• .insertAdjacentHTML()
• .previousElementSibling
• .parentElement
• .remove()

Note: Unless you are submitting data to a server, add type="button" to each <button>

Details are commented in code below

 // Refernce <form> const form = document.forms.commentsReplies; // Any click on <form> invokes post() form.onclick = post; // Pass the event function post(event) { /* Reference all <fieldset> (also <button>, <textarea>, etc) */ const field = event.currentTarget.elements; // Reference the actual element clicked const clicked = event.target; // if element clicked has class postCom if (clicked.matches('.postCom')) { /* find <fieldset name="post"> and insert HTML into it */ field.post.insertAdjacentHTML('beforeEnd', `<fieldset name='commentPost'><textarea></textarea><button class='comTxt' type='button'>Done</button></fieldset>`); // Otherwise if clicked element has class comTxt } else if (clicked.matches('.comTxt')) { /* find the clicked element's element that is right before it and get it's text */ const text = clicked.previousElementSibling.value; /* find <fieldset name='comments'> and insert HTML */ field.comments.insertAdjacentHTML('afterBegin', `<fieldset>${text}<button class='postRep' type='button'>Reply</button><ul></ul></fieldset>`); // Remove <fieldset name='commentPost'> field.commentPost.remove(); } else if (clicked.matches('.postRep')) { clicked.insertAdjacentHTML('afterEnd', `<ul><textarea></textarea><button class='repTxt' type='button'>Done</button></ul>`); } else if (clicked.matches('.repTxt')) { const text = clicked.previousElementSibling.value; const list = clicked.parentElement; list.insertAdjacentHTML('afterBegin', `<li>${text}<button class='postRep' type='button'>Reply</button></li>`); clicked.previousElementSibling.remove(); clicked.remove(); } else { return false; } }

 button { display: block; margin-left: 25%; }

 <form id='commentsReplies'> <fieldset name='post'><button class='postCom' type='button'>Leave a comment</button> </fieldset> <fieldset name="comments"> <legend>Comments</legend> </fieldset> </form>