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.

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.

• javascript
• php
• jquery
• mysql
• ajax

• Possible duplicate of Pass a PHP string to a Javascript variable (and escape newlines) and a gazillion others. – deceze ♦ Commented Aug 15, 2013 at 10:51
• 1 I wonder why they spent hours/days making the manual? – Niet the Dark Absol Commented Aug 15, 2013 at 10:52
• For that purpose you can use $.ajax in jquery – Rohitashv Singhal Commented Aug 15, 2013 at 10:52

3 Answers 3

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; ?>";

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));
}

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;?>";
            });
        }
    });
});