Question

I got a syntax error on the following code. Once I took out the first line of code, the alert pops. My brain is almost dead and I can’t find out why. Please help. Thanks a lot.

JS

var rss = <?php echo json_encode($test); ?>;

alert("Hello World");

Updated

html

  <?php 

    $test=get_array(); 

   //the $test is a multi-dimention array.

  ?>


<script type="text/javascript" src="js/slideshow.js"></script>

Answer 1

json_encode will return FALSE on failure, so if it fails, echo false will output nothing.

so your code became below, which give you a syntax error.

var rss = ;

alert("Hello World");

Edit:
From your updated edit, the reason is:
You can not write php code in a js file.

If you need that variable in the js file, assign it to a global variable first.

<script type="text/javascript">
  var rss = <?php echo json_encode($test); ?>;
</script>
<script type="text/javascript" src="js/slideshow.js"></script>