HTML Form POST is null

问题:

so I'm trying to simply send one field of data from a form to a php file. Below is my form in a table. I also posted my php code. It keeps returning that $username is null. Ive tried post/get and it doesn't seem to matter.

HTML:

<form action='http://k9minecraft.tk/scripts/adduser.php' method='POST'>
<table>
<tr>
<td>First Name:</td>
<td><input type='text' id='first'></td>
</tr>
<tr>
<td>Last Name:</td>
<td><input type='text' id='last'></td>
</tr>
<tr>
<td>Email:</td>
<td><input type='text' id='email'></td>
</tr>
<tr>
<td>Minecraft Name:</td>
<td><input type='text' name='user'></td>
</tr>
<tr>
<td><input type='submit' value='Send'></td>
<td><input type='reset' value='Reset'></td>
</tr>
</table>
</form>

PHP:

<?php
print_r($_POST);
    if(isset($_POST['user'])){
        $username = $_POST['user'];
        echo $username;
        echo 'username is not null';
        }
?>

回答1:

This code is working. You need to add some condition, that checks, if $username is posted or not.

Something like that:

if(count($_POST)){
    $username ='';
    if(isset($_POST['user'])){
        $username = $_POST['user'];
    if ($username==null || !$username)
         echo 'username is null';
     echo strlen($username);
     echo $username;
   }

 }

回答2:

The issue is that all of your inputs have ids but not names. The ids are used by JavaScript. The names are used for posting.

Change it to be like this:

<form action='http://k9minecraft.tk/scripts/adduser.php' method='POST'>
<table>
<tr>
<td>First Name:</td>
<td><input type='text' name='first' id='first'></td>
</tr>
<tr>
<td>Last Name:</td>
<td><input type='text' name='last' id='last'></td>
</tr>
<tr>
<td>Email:</td>
<td><input type='text' name='email' id='email'></td>
</tr>
<tr>
<td>Minecraft Name:</td>
<td><input type='text' name='user'></td>
</tr>
<tr>
<td><input type='submit' name='Send' value='Send'></td>
<td><input type='reset' name='Rest' value='Reset'></td>
</tr>
</table>

回答3:

Try this to find out if the field is posted by the formular:

isset($_POST['user'])

I think $username==null will be true even if $username really is equal to an empty string.

回答4:

This is how people usually do it:

if(isset($_POST['user']) && !empty($_POST['user'])) {
    $user = $_POST['user'];
}

Note: == null will not work with empty string. see here.

You also need to add a name attribute for other input fields of yours.

回答5:

try using this

<?php
    if(isset($_POST['submit'])){
     $msg = "";
     /* Validate post */
     if(isset($_POST['user'])==""){
      $msg .= "username is null";
     }
    /*End Validate*/
     if($msg==""){
      $user = $_POST['user'];
     }else{
       echo $msg;
     }
    }

?>