jQuery Comment Preview

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I released a MooTools comment preview script yesterday and got numerous requests for a jQuery version. Ask and you shall receive! I'll use the exact same CSS and HTML as yesterday.


<div id="live-preview-form" class="lp-block">
		<strong>Your Name:</strong><br />
		<input type="text" name="name" id="name" value="" class="input" /><br /><br />
		<strong>Your Email:</strong><br />
		<input type="text" name="email" id="email" value="" class="input" /><br /><br />
		<strong>Your Website:</strong><br />
		<input type="text" name="website" id="website" value="" class="input" /><br /><br />
		<strong>Your Comment:</strong><br />
		<textarea name="comment" id="comment" class="input" rows="10"></textarea>

<div id="live-preview-display" class="lp-block">
	<div id="lp-avatar"></div>
	<div id="lp-name"></div>
	<div id="lp-comment"></div>


.lp-block		{ width:400px; float:left; }
.lp-block input, .lp-block textarea { width:90%; }
#live-preview-display 	{ background:#eee; padding:10px; margin-left:50px; margin-top:20px; }
#lp-name { font-weight:bold; }
#lp-avatar { float:right; margin:0 0 20px 20px; }
#lp-comment { padding-top:10px; font-style:italic; line-height:19px; }

The jQuery JavaScript

$(document).ready(function() {
	var commentNode = $('#lp-comment'),
		nameNode = $('#lp-name'),
		name = $('#name'),
		website = $('#website');
	$('#live-preview-form input, #live-preview-form textarea').bind('blur keyup',function() {
		commentNode.html($('#lp-comment').html().replace(/\n/g,'<br />'));
		//name & websites
		if($('#name').val()) {
			if(website.val() && /http:\/\/[A-Za-z0-9\.-]{3,}\.[A-Za-z]{2}/.test(website.val())) {
				nameNode.html('<a href="' + website.val() + '">' + name.val() + '</a> says:');
			else {
				nameNode.text(name.val() + ' says:');
		if($('#email').val() && /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/.test($('#email').val())) {
				var md5Email = MD5($('#email').val());
				$('#lp-avatar').html('<img src="http://www.gravatar.com/avatar.php?gravatar_id=' + md5Email + '&size=80&rating=G&default=http%3A%2F%2Fdavidwalsh.name%2Fwp-content%2Fthemes%2Fdavid-walsh%2Fgraphics%2Fcom.jpg" alt="' + $('#lp-name').val() + '" />');

On the keypress and blur events, we validate and format the commenter's name, avatar, website, and comments as necessary. As with yesterday's MooTools post, the MD5 function can be found here.

Too easy!

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  1. Brilliant, thank you very much :)

  2. I would perhaps use the keyup rather than keypress event, so that the final character you type appears without you having to move your focus away from the textarea.

    Otherwise, really nice :)

  3. I agree with the keyUp comment, but still very nice!

  4. Changed to keyup. I didn’t notice at first — i must type too fast.

  5. Javier Martinez

    You are the best…!

  6. Noticed a bit of jumping in FF, try throwing a min-height on your display div to fix that (won’t work in IE 6 of course but eh.) Great job though, post via AJAX for a next step?

  7. I just implimented this on my site. At first I was including the md5 function on an external file and firebug was saying that the function was undefined, however when I put it straight on the document it worked fine.

    The filename was definatly correct. Would there be any other reason for this?

  8. @Ben: Hard to say without seeing the page/code.

  9. Thanks for taking the time to port this to jQuery David, you’re the beez neez.

  10. holy crap that’s cool, I really need to start learning javascript.

  11. Pockata

    It’s nice bro, but just one thing. It would be nice to use some line-breaking function, so when the word is too long it goes out of the box :) U can use this JS Wordwrap .

  12. very very nice! what a nice feature for the visitors. thank you for sharing!

  13. Thank’s, very nice!

  14. oh my god this is so sick!

    Man I loved that!!!

    Brilliantly awesome dude!!!

  15. Is it possible to make it process HTML tags? For example TEXT would make “TEXT” appear bold?

  16. @James Wong:

    Try changing



  17. @Ben: Like magic! works like a charm :D ty

  18. Johnny

    i noticed that the gravatar does not work it always shows the default gravatar
    any sugestions on how to fix that (i thought it might be it needs to pass the email in lowercase){i dont know jquery much so i dont know if its doing that}

    i am currently trying to convert the md5 and as meny things as i can to php so can save the data in mysql and use on my site. but im a bit lost and its driving me nuts
    i did get php to work with gravatar on my site.

    any help would be grate to convert this to a jquery/php with save features
    i did find a nifty mysql jquery routine
    that has the mysql routines to use for coments
    so any ideas on how to incorp all this and to fix the bug of only displaying the default gravatar?

    thank you in advance for any code or help you may provide

  19. Johnny

    this is the php is has the problem of not displaying the default gravatar
    go figure
    $email = "dragonsworkshop@yahoo.com";
    $default = "http//:davidwalsh.name/wp-content/themes/david-walsh/graphics/com.jpg";
    $size = 50;

    //You can construct your gravatar url with the following php code:

    $grav_url = "http://www.gravatar.com/avatar.php?gravatar_id=&quot;.md5( strtolower($email) ).

    echo '’;


  20. Johnny

    echo ‘IMG SRC=”‘.$grav_url.'” ALT=”?” BORDER=0’;
    add a less then and greater then signs for image (didnt print in last post thought it was html)

  21. Johnny

    this now works fixed the default image php code

    function validate_gravatar($email) {
    	// Craft a potential url and test its headers
    	$hash = md5($email);
    	$uri = 'http://www.gravatar.com/avatar/' . $hash . '?d=404';
    	$headers = @get_headers($uri);
    	if (!preg_match("|200|", $headers[0])) {
    		$has_valid_avatar = FALSE;
    	} else {
    		$has_valid_avatar = TRUE;
    	return $has_valid_avatar;
    $email = "11111xxxxx@yahoo.com";
    $default = "http://davidwalsh.name/wp-content/themes/david-walsh/graphics/com.jpg";
    $size = 50;
    //You can construct your gravatar url with the following php code:
  22. Johnny

    had to split the code(wouldn’t let me post thought i was spam)

    $grav_url = “http://www.gravatar.com/avatar.php?gravatar_id=”.md5( strtolower($email) ).

    if (validate_gravatar($email))
    echo ‘IMG SRC=”http://’.$grav_url.'” ALT=”?” BORDER=0′;

    echo ‘no gravatar found’;
    echo ‘IMG SRC=”‘.$default.'” ALT=”?” BORDER=0’;
    echo “org gravatar”;
    echo ‘IMG SRC=”‘.$grav_url.'” ALT=”?” BORDER=0’;

    // replace less then and greater then signs for image as needed

  23. Thanx I really needed a comment box you’ve saved my life

  24. Here’s my version, dating from the year 2005 (onkeyup="ReloadTextDiv()" on the textarea) – short and sweet:

    // live comment preview  - comment body 
    function ReloadTextDiv() { 
    document.getElementById('CommentDisplay').innerHTML = ''+document.getElementById('requiredcomment').value.replace(/(\r\n|\n)/g,'').replace(/(){2,}/gi,'')+'';
    // by default do not show the commentsheader and preview until something is typed in either name or text
  25. Hello,

    More than 15 characters (And stop at 255 characters) long when I want to run. But it did not work. Please help me,

    $('#commentsForm textarea').bind('blur keyup',function() {
    if($('#comment').length > 15){

    Samet ARAS.

  26. M

    @Ben: great

    @Rob Simpkins: great great great great great great

  27. Matt T

    I have a form with three selection menus. but every time i run this script I’m have trouble getting only one selection menu to how it’s change in it’s corresponding #sum_… div

    If i change the value of the #game_time selection menu, the other two selection menus also change their value,

    How can i stop this?

    Here is my current script

    $(document).ready(function() {
    	$('#form select, #summary').bind('blur change',function() {


  28. Matt T

    I have a form with three selection menus. but every time i run this script I’m have trouble getting only one selection menu to how it’s change in it’s corresponding #sum_… div

    If i change the value of the #game_time selection menu, the other two selection menus also change their value,

    How can i stop this?

    Here is my current script

    $(document).ready(function() {
    	$('#form select, #summary').bind('blur change',function() {


  29. Anderson

    Hi all, am new to JQuery & i need to add comments/Post on my website am develpoing. please i can any one help me with a demo or link to get a download?


  30. Donald

    @chris: u re right man

  31. Just what I was looking for – thank you for sharing.


  32. Is nice when is all script untul finish, and how the next script that show the comments?


  33. nick

    why wont this text allow you to style links and bold and italic font in the preview? is there an easy way to do that?

    • $('#lp-comment').html($('#lp-comment').html()
      	.replace(/\n/g		, '')
      	.replace(/\[b\]/g	, '').replace(/\[(\/)b\]/g		, '')
      	.replace(/\[list\]/g, '').replace(/\[(\/)list\]/g	, '')
      	.replace(/\[\*\]/g	, '').replace(/\[(\/)\*\]/g		, '_'));

      Sorry guy for my poor english…
      , but you do remove the “_” before and after tag ()

  34. I’m a newb to programming/coding and this is probably a stupid question to you guys… where do I paste the jquery code?

    Thanks for the help

    • danny


  35. Adil Khan

    Hi david, Can you say me that how to make a comment box for my website which the people will use to post comments on my website.
    The same like which you have,
    Please Reply Soon….


  36. nadun

    hey..good post dud…but this download link is not..can you add with zip file it..i think very important all of…thank u……….


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    comments adasdasdasdasdasdasdasd

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    How would add this to blogger , i need to change bloggers format, i dont no how?

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    Please tell me , what is a sumbit button for this script ??

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