Undefined Index in PHP $_POST Array - php

Question

I've a page index.php where I added a search form that's connected with the database. So that When users search any word, result would show up from database. Once results generated on the page I want users to export the result into a .doc file.
I want only the query results into the .doc file but for some reasons I'm getting a blank .doc file.
Here are my codes:
searchform:
<form id="searchform" method="post">
<input type="text" name="searchit" id="searchit" class="txt" />
<input type="submit" value="Search" id="button" class="button" />
</form>
Query:
<?php
include("database.php");
$term = strip_tags(substr($_POST['searchit'],0, 100));
$term = $mysqli->real_escape_string($term);
if($term=="") {
echo "<div class='error'>Enter Something to search</div>";
exit();
}
termcheck($term, $mysqli);
function termcheck($term, $mysqli){
$qry="Select * from pogel where title = '$term'";
if($result = $mysqli->query($qry)){
$num_rows = $result->num_rows;
if($num_rows > 0) {
while($row = $result->fetch_assoc())
{
echo "Stem : ".$row['title']."<br>";
}
}
}
}
?>

Answer 1

Seems like you just don't have this key in your POST.
You may try this if no such element comes to script:
$searchit = filter_input(INPUT_POST, 'searchit');
if(!$searchit) {
echo "<div class='error'>Enter Something to search</div>";
exit();
}
$term = strip_tags(substr($searchit,0, 100));
$term = $mysqli->real_escape_string($term);
Try this to generate doc file:
<?php
include("database.php");
$term = strip_tags(substr($_POST['searchit'],0, 100));
$term = $mysqli->real_escape_string($term);
if($term=="") {
echo "<div class='error'>Enter Something to search</div>";
exit();
}
$output = termcheck($term, $mysqli);
function termcheck($term, $mysqli){
$qry = "Select * from pogel where title = '$term'";
$result = '';
if($result = $mysqli->query($qry)){
$num_rows = $result->num_rows;
if($num_rows > 0) {
while($row = $result->fetch_assoc()) {
$result .= "Stem : ".$row['title']."<br>";
}
}
}
return $result;
}
ob_flush();
header("Content-type: application/vnd.ms-word");
header("Content-Disposition: attachment;Filename=document_name.doc");
echo $output;
//ob_flush_clean() might be useful here, but not sure
?>