title: How to validate forms when a user changes the name of an input element in firebug?
body: <p>I realize it's impossible to prevent someone from changing the names of input elements in firebug.</p>
  
  <p>How should I approach this problem?  A user changes the name of the input element "firstname" to "month" and visa versa.</p>
  
  <pre><code>&lt;form action="example.php" method="post" enctype="multipart/form-data"&gt;
      &lt;table  border='2'&gt;
          &lt;tr&gt;
              &lt;td&gt;
                  First name: &lt;input type="text" name="firstname" /&gt;&lt;br /&gt;
              &lt;/td&gt;
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td&gt;
                  Last name: &lt;input type="text" name="lastname" /&gt;&lt;br /&gt;
              &lt;/td&gt;
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td&gt;Birth Month:
                  &lt;select name="month"&gt;
                      &lt;option value="01"&gt;January&lt;/option&gt;
                      &lt;option value="02"&gt;February&lt;/option&gt;
                      &lt;option value="03"&gt;March&lt;/option&gt;
                      &lt;option value="04"&gt;April&lt;/option&gt;
                      &lt;option value="05"&gt;May&lt;/option&gt;
                      &lt;option value="06"&gt;June&lt;/option&gt;
                      &lt;option value="07"&gt;July&lt;/option&gt;
                      &lt;option value="08"&gt;August&lt;/option&gt;
                      &lt;option value="09"&gt;September&lt;/option&gt;
                      &lt;option value="10"&gt;October&lt;/option&gt;
                      &lt;option value="11"&gt;November&lt;/option&gt;
                      &lt;option value="12"&gt;December&lt;/option&gt;
                  &lt;/select&gt;
                  &lt;br /&gt;
              &lt;/td&gt;   
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td&gt;&lt;input type="submit" name="Submit" value="Sign Up!" /&gt;&lt;/td&gt;
          &lt;/tr&gt;
      &lt;/table&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>My best idea so far is:</p>
  
  <pre><code>&lt;?php
  $month= $_POST['month'];
  if($month!= 01 || $month!= 02 ... $month!= 12)
      echo 'wrong month';
  ?&gt;
  </code></pre>
  
  <p>However this won't be clean for the year of birth... Facebook does a great job of preventing this when you sign up but I wasn't able to figure out what they did.  A non-javascript solution would be much appreciated.</p>
  
  <p>EDIT: Lawrence, what do you recommend for a location form?</p>