ส่งค่า php ไปให้ javascript เเล้วทำไมค่าถึงไม่ไปครับ

<?php
echo "<script type='text/javascript'>";
	echo "function show(num, txt){";
		echo "document.getElementById('testTxt').innerHTML= txt;";
                echo "document.getElementById('testNum').innerHTML= num;";
	echo "}";
echo "</script>";
?>

<?php

$num = 1234;
$txt= "test";

echo "<div id="testTxt">show txt</div>";
echo "<div id="testNum">show num</div>";

echo "<a href='#' onClick='show($num,$txt)'>Click test</a>";

?>