how do I redirect to a url

I have a project that no one can or wants to engage in. The data is in a database table.
The code displays a menu, selects a target (url - http://.....), displays the record - so
far so good....then I want to click the button and redirect to the url.... not so good.
Can someone please advise.

<!DOCTYPE><html><head><title>lookup menu</title></head>
<body><center>
<form name="form" method="post" action="">
<?php
$con=mysqli_connect("localhost","root","","homedb");
//============== check connection
if(mysqli_errno($con))
{echo "Can't Connect to mySQL:".mysqli_connect_error(); exit; }
else
{echo "Connected to mySQL</br>";}
//This creates the drop down box
echo "<select name= 'target'>";
echo '<option value="">'.'--- Select lookup account---'.'</option>';
$query = mysqli_query($con,"SELECT target FROM lookuptbl");
$query_display = mysqli_query($con,"SELECT * FROM lookuptbl");
while($row=mysqli_fetch_array($query))
{echo "<option value='". $row['target']."'>".$row['target']
.'</option>';}
echo '</select>';
?>
<p><p>
<CENTER>then

<input type="submit" name="submit" value="Submit"/>
</form>
<?php
if(isset($_POST['target']))
{
$name = $_POST['target'];
$fetch="SELECT id, target, username, password, purpose, emailused,lastused,
count FROM lookuptbl WHERE target = '".$name."'";
$result = mysqli_query($con,$fetch);
if(!$result)
{echo "Error:".(mysqli_error($con));}
//display the table
echo '<table border="1">'.'<tr>'.'<td bgcolor="#ccffff align="center">'. 'lookup menu'. '</td>'.'</tr>';
echo '<tr>'.'<td>'.'<table border="1">'.'<tr>'.'
<td bgcolor="#CFB53B align="center">'.'id'.'</td>'.'
<td bgcolor="#CFB53B align="center">'.'target'.'</td>'.'
<td bgcolor="#ccffff align="center">'.'username'.'</td>'.'
<td bgcolor="#ccffff align="center">'.'password'.'</td>'.'
<td bgcolor="#ccffff align="center">'.'purpose'. '</td>'.'
<td bgcolor="#ccffff align="center">'.'emailused'.'</td>'.'
<td bgcolor="#CFB53B align="center">'.'lastused'.'</td>'.'
<td bgcolor="#CFB53B align="center">'.'count'. '</td>'.'</tr>';
while($data=mysqli_fetch_row($result))
{echo ("<tr><td>$data[0]</td><td>$data[1]</td><td>$data[2]</td><td>$data[3]</td>
<td>$data[4]</td><td>$data[5]</td><td>$data[6]</td><td>$data[7]</td></tr>");}
echo '</table>'.'</td>'.'</tr>'.'</table>';
$id="id";
$target="target";
$count="count";
$lastused="lastused";
$sql = "UPDATE lookuptbl SET lastused=NOW(), count=$count + 1 WHERE target=$target";
if ($con->query($sql) === TRUE) { echo "Record updated successfully"; }
else { echo "Error updating record: " . $con->error; }
}
?>
<p>
<button onclick="myFunction('<?php echo $target;?>')">go to url</button>
<?php
?>
</body></html> 

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