how to use variable from php in javascrtipt code example

Example 1: javascript access php variable

//passing PHP variable to JavaScript
var myJSVar = <?php echo json_encode($myPHPVar); ?>;

Example 2: how to get a variable from php to javascript

<script type="text/javascript">
// boolean outputs "" if false, "1" if true
var bool = "<?php echo $bool ?>"; 

// numeric value, both with and without quotes
var num = <?php echo $num ?>; // 7
var str_num = "<?php echo $num ?>"; // "7" (a string)

var str = "<?php echo $str ?>"; // "A string here"
</script>