Wordpress php undefined index with form posting to db


Staff member
I am building a very small form for a wordpress widget. The form is just a drop down select input that allows users to select their business type - this is then stored in the wp_usermeta table in the database.

The dropdown is actually selected on registration, so this form is more of an opportunity for users to change the value.

Here is the php I am using to create the form:

$user = wp_get_current_user();        
$selected = get_user_meta( $user->ID, 'i_am_a', true ); 

<form method="post">        
<h3>I am a...</h3>
        <select name="i_am_a" id="i_am_a">
            <option value="musician" autocomplete="off" <?php echo ($selected == "musician")?  'selected="selected"' : '' ?>>Musician/Artist</option>
            <option value="band" autocomplete="off" <?php echo ($selected == "band")?  'selected="selected"' : '' ?>>Band</option>
            <option value="photographer" autocomplete="off" <?php echo ($selected == "photographer")?  'selected="selected"' : '' ?>>Photographer</option>
            <option value="business" autocomplete="off" <?php echo ($selected == "business")?  'selected="selected"' : '' ?>>Small Business</option>
            <option value="other" autocomplete="off" <?php echo ($selected == "other")?  'selected="selected"' : '' ?>>Other</option>
<input type="submit" name="submit" value="change" class="button"/>

    $i_am_a = $_POST['i_am_a'];
    update_user_meta( $user->ID, 'i_am_a', $i_am_a );

Notice: Undefined index: i_am_a in /home/.../layers-whitelabel.php on line 90

Line 90 is as follows:

$i_am_a = $_POST['i_am_a'];

How can I get rid of this error?