How to send php variable to AJAX

Question

I need to retrieve session variable data inside an ajax call. Here is my try.

$('#update').click(function(){ 
 
 
 var number = $('#num').val();
 var curuser = <?php echo $_SESSION['userName'];?>
 
 if( number != '' && number.length==9 )
 {
 
 $.ajax({
 data:{number:number},
 success:function(data){ 
 
 $('#number_add').val(number); 
 $('#new_data_Modal').modal('show'); 
 } 
 
 });
 }
 
 
 });

Seems like var curuser = <?php echo $_SESSION['userName'];?> prevents opening my model(new_data_Modal) after button(update) click. When I remove that line it works fine(Model is opening as previous).

But alert("<?php echo $_SESSION['userName'];?>") is working and it prints the session variable as well.

Can someone show me where I made the wrong?

• yaroslavche: wrap <?php echo $_SESSION['userName'];?> with quotes, because in your example in result you would have sth like following: var curuser = userNameValue which is not valid code in JS (if it would return string value). Also one suggestion (not really important) consider using let (mutable) and const (immutable) instead var.

Answer 1

If this is a string you need to wrap the variable in quotes:

var curuser = '<?php echo $_SESSION['userName'];?>';

otherwise, when PHP code is executed you will get a syntax error:

var curuser = John

You can check the source code of the generate HTML to see what is the output.

NOTE: Your javascript code needs to be a PHP file with a PHP extension, it can be your HTML or JavaScript file. You can use JS file as PHP script in script tag <script src="code.php"></script>

Answer 2

If you're outputting JavaScript values from your php script you should use json_encode, that way any data type will work and there is no risk of your code breaking if you data has a quote or new line in it.

var curuser = <?php echo json_encode($_SESSION['userName']);?>