Keep input value after refresh page
<p>I have a form with input field and this input contain a drop down menu read information from database.
If the user enters value and when he arrives to the drop menu he doesn't find what he wants he go to another page to add this info to the drop down menu and then go to the first page to continue enter the information.
How can I keep this information if he goes to another page to add info to drop menu and how can after adding the info to drop menu find this info without refresh and without submit.</p>

<p>This is the first page with the form</p>

<pre><code>&lt;form name='' method='post' action='&lt;?php $_PHP_SELF ?&gt;'&gt;
&lt;input name='txt_name' id='' type='text'&gt;
</code></pre>

<p>This drop menu read from database</p>

<pre><code> &lt;select id="groups" name="txt_label" class="form-control"&gt;
   ';?&gt;
     &lt;?php 
    $sql=mysqli_query($conn,"select DISTINCT db_label from tbl_label")or die(mysqli_error($conn));
 echo'&lt;option  value=""&gt;-- Select --&lt;/option&gt;';
    while($row=mysqli_fetch_array($sql)){
        $label=$row['db_label'];
        echo "&lt;option value='$label'&gt;$label&lt;/option&gt;"; 
    }echo'&lt;/select&gt;';?&gt;&lt;?php echo'
  &lt;/div&gt;
&lt;/form&gt;
</code></pre>

<p>Second form in another page</p>

<pre><code>&lt;form class="form-inline" role="form" name="form" method="post" action="';?&gt;&lt;?php $_PHP_SELF ?&gt;&lt;?php echo'"&gt;
    &lt;div class="form-group"&gt;
    &lt;label for="pwd"&gt;Label&lt;/label&gt;
  &lt;input id="txt_label" name="txt_label" type="text" placeholder="Label" class="form-control input-md"&gt;
  &lt;/div&gt;
   &lt;div class="form-group"&gt;
    &lt;label for="pwd"&gt;Sub Label&lt;/label&gt;
  &lt;input id="txt_sublabel" name="txt_sublabel" type="text" placeholder="SubLabel" class="form-control input-md"&gt;
  &lt;/div&gt;
   &lt;input type="submit" name="addlabel" value="Add" class="btn btn-default"&gt;';
</code></pre>