assign php variable to javascript variable

Question

How can i assign value of a javascript variable using php variable

 $(function(){
    $("select[name=myselectlist]").change(function(){
        var id = $(this).val();
        if(id != 0) {       
            $.post("ajax.php", {"id":id}, function(){
                var data = "somedatahere";
                document.getElementById("namesurname").value = data;
            });
        }
    });
});

the code above works perfectly without php.Yet, i need to assign "var data" from mysql everytime.

Possible duplicate of [Pass a PHP string to a Javascript variable (and escape newlines)](http://stackoverflow.com/questions/168214/pass-a-php-string-to-a-javascript-variable-and-escape-newlines) and a gazillion others. — deceze, Aug 15 '13 at 10:51
[I wonder why they spent hours/days making the manual?](http://php.net/json-encode) — Niet the Dark Absol, Aug 15 '13 at 10:52

score 6 · Answer 1 · answered Aug 15 '13 at 10:56

6

If your php var is in the scope of the file where you have this function, you can do it like this:

var data = "<php echo $myvar; ?>";

answered Aug 15 '13 at 10:56

Sahil Mittal

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Note: even if php var doesnt belong here you can assign the SESSION variable similarly – Sahil Mittal Aug 15 '13 at 11:00
idk why but it doesnt work for me, i mean when i use like; document.getElementById("namesurname").value = ; value of text field with namesurname id doesnt change. – Burak KOÇAK Aug 15 '13 at 12:02
Try with the php var in quotes. If not worked cross check that $data['name'] is valid – Sahil Mittal Aug 15 '13 at 12:46

kryoz · Answer 2 · 2013-08-15T11:39:39.573

1) You can do as Shadowfax wrote but more simple:

var data = '<?=$dbResult?>';

2) More correct. Pass your result to AJAX response with json_encode function in PHP so you can rewrite your JavaScript code block as follows:

...
$.post("ajax.php", {"id":id}, function(response){
    $("#namesurname").val(response.data);
});

For example your PHP code block in backend may look like this:

....
if (isset($_SERVER['HTTP_X_REQUESTED_WITH']) AND strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) === 'xmlhttprequest')) {
    echo json_encode(array('data' => $dbResult));
}

score 1 · Answer 3 · answered Aug 15 '13 at 10:58

If this javascript code is in the php file, then you can simply use php variables as updated in the code:-

<?php
// assign a value
$data = 'your data here';
?>

$(function(){
    $("select[name=myselectlist]").change(function(){
        var id = $(this).val();
        if(id != 0) {       
            $.post("ajax.php", {"id":id}, function(){
                var data = "somedatahere";
                document.getElementById("namesurname").value = "<?php echo $data;?>";
            });
        }
    });
});

assign php variable to javascript variable

3 Answers3