如何将PHP变量的值插入到javascript代码中？

I need to insert a value from php code into the page for use in javascript.

<script type="text/javascript">
  window.jQuery || document.write("<script src='assets/js/jquery1x.min.js'>"+"<"+"/script>");
</script>

and this is PHP:

<?php echo WEB_ROOT; ?>

i need to insert here:

<?php echo WEB_ROOT; ?>assets/js/jquery1x.min.js

How can i do?

Thanks!

Just simply echo it

<script type="text/javascript">
   window.jQuery || document.write("<script src='<?php echo WEB_ROOT; ?>assets/js/jquery1x.min.js'>"+"<"+"/script>");
</script>

And even if your code is separate file, you can still rename it to .php and include in html

<script src="file.php"></script>