Without searching a value it displays no record - php

Question

In this below code i am searching a value.if the value is searched it displays the result but if the value is not present it should displays no result. In my case if i execute and not search any value it displays no record .Please any one help me.
<form action="<?php echo site_url('search1_site/index');?>" method = "post">
<input type="text" name = "keyword" />
<input type="submit" id="opn" value = "Search" />
</form>
<?php
if($results){
?> <div id='hideme'>
CLOSE<a href='#' class='close_notification' title='Click to Close'>
<img src="<?php echo base_url('img/close.png'); ?>" width="15" height="15" alt="Close" onClick="hide('hideme')"/>
</a> <div style="background:#FFFFFF; width: 500px; height: 500px; position: absolute; left: 50%; top: 50%; margin-left: -100px; margin-top: -100px" id="modal" >
<table class="display2 table table-bordered table-striped">
<tr>
<th>course_code</th>
<th>course name</th>
</tr>
<tr><?php
foreach ($results as $row) {
?>
<td><?php echo $row->course_code;?></td>
<td><?php echo $row->course_name;?></td>
</tr>
<?php
}
}else{
echo "no results";
}
?>
</table></div></div>
<script>
$('a.modal').bind('click', function(event) {
event.preventDefault();
$('#modal').fadeIn(10);
});
function hide(obj) {
var el = document.getElementById(obj);
el.style.display = 'none';
}
</script>

Answer 1

Try adding name attribute to your submit button and check if it's set before the if...else block.
<!-- HTML -->
<input type="submit" name="submit" id="opn" value = "Search" />
// PHP
<?php
if (isset($_POST['submit'])) { // Here
// Do the search here
if($results){
?> <div id='hideme'>
CLOSE<a href='#' class='close_notification' title='Click to Close'>
<img src="<?php echo base_url('img/close.png'); ?>" width="15" height="15" alt="Close" onClick="hide('hideme')"/>
</a> <div style="background:#FFFFFF; width: 500px; height: 500px; position: absolute; left: 50%; top: 50%; margin-left: -100px; margin-top: -100px" id="modal" >
<table class="display2 table table-bordered table-striped">
<tr>
<th>course_code</th>
<th>course name</th>
</tr>
<tr><?php
foreach ($results as $row) {
?>
<td><?php echo $row->course_code;?></td>
<td><?php echo $row->course_name;?></td>
</tr>
<?php
}
}else{
echo "no results";
}
} // If closing
?>
Is this something similar to what you're looking for?

Answer 2

If the variable $results is array of results use something like this:
if (count($results) > 0)
{
// show results
} else
{
echo "No results";
}