javascript - Error messages on contact form -

right now, i'm validating contact form using java/ajax, , generating error messages in javascript following

messages:  {     fname: "please fill in name",     email: "your email contact you",     subject: "please fill in subject of message",     recipient: "please let know contact",     message: "please fill out message",     captcha: "please answer 2x3" } 

which generates

<label class="error">the error message id</label>.

i'm not sure how label generated, i'm wanted replace empty text inputs value of error message when it's not filled out.

i've tried using

fname.value = "the error message";

but doesn't seem work. ideas on how error message show within input instead of generating label?

form markup:

<form name="myform" id="myform" action="" method="post">     <fieldset>         <label for="fname" id="name_label">first name</label>          <input type="text" name="fname" id="fname" value="">          <label for="lname" id="lname_label">last name</label>          <input type="text" name="lname" id="lname" value="">     </fieldset>     <fieldset>         <label for="email" id="email_label">email</label>          <input type="text" name="email" id="email" value="">          <label for="phone" id="phone_label">phone number</label>          <input type="phone" name="phone" id="phone" value="">     </fieldset>     <fieldset>         <label for="message" id="message_label">message</label>          <textarea name="message" id="message" size="30" value=""></textarea>          <label for="captcha" id="captcha_label">what's 2x3?</label>          <input type="text" name="captcha" id="captcha" value="">     </fieldset><     input type="submit" name="submit" value="submit"> </form> <p>     <img src="%3c?php%20echo%20get_template_directory_uri();%20?%3e/images/loader.gif" id="loading" alt="loader" name="loading"> </p> <div id="results"></div> 

use following js:

document.myform.fname.value = messages_parent_obj.messages.fname; 

i've put jsfiddle here: http://jsfiddle.net/dwywe/ (note wrapped messages in parent object since snippet implied there one).