My search form does not seem to work - php

Question

I want my search form to display users(username,firstname or lastname) from my database and display them as the user is typing like how facebook and twitter do but when i click search,nothing happens.Here are 2 parts of my header inc that deal with the search form,1st part:
<?php
include( "Connect.php" );
ob_start(); session_start();
if (isset($_SESSION['user_login'])) {
$user = $_SESSION["user_login"];
}
else {
$username = "";
}
$output = "";
//Collect
if(isset($_POST['search'])) {
$searchq = $_POST['search'];
$searchq = preg_replace("#[^0-9a-z]#i","",$searchq);
$query = $mysqli->query("SELECT * FROM users WHERE first_name LIKE '%$searchq%' OR last_name LIKE '%$searchq%'") or die("could not search!");
$count = mysqli_num_rows($query);
if($count == 0) {
$output = 'There was no search results!';
} else {
while($row = mysqli_fetch_array($query)) {
$fname = $row['first_name'];
$lname = $row['last_name'];
$id = $row['id'];
$output .= '<div> '.$fname.' '.$lname. '</div>';
}
}
}
?>
2nd part:
<form id="searchForm">
<fieldset>
<div class="input">
<p>
<form action="header inc.php" method="post">
<input type="text" class="Search" id="search" size="35" placeholder="Search username,fullname or topic"/>
<label for="Submit"></label>
<input type="submit" name="search" value="Go" id="search" />
</p>
</div>
</form>
<?php print ("$output"); ?>

Answer 1

invalid action name
action="header inc.php"
you cannot use space in .php files
Edit the filename as headerInc.php and pass it in the form as:
action="headerInc.php"

Answer 2

I have changed your html code , just use it and it will start working. In your html there is hierarchy of form tag , I have added method post to first form and I have replaced the name of the text field by submit button name. In each post your data value was "go".
I hope it will resolve your problem :
<form id="searchForm" method="post">
<fieldset>
<div class="input">
<p>
<form action="header inc.php" method="post">
<input type="text" class="Search" name="search" id="search" size="35" placeholder="Search username,fullname or topic"/>
<label for="Submit"></label>
<input type="submit" value="Go" id="search_button" />
</p>
</div>
</form>
<?php echo $output; ?>