我们如何在php的帮助下从mysql数据库中分配一个javascript数组？

Question

I would like to know if we can select data from the database using php and assign it to a javascript array? if so what would be the syntax?

I wrote the code below but it is not working

$js_array = "[";
$result = mysql_query("SELECT item_name FROM tbl_item");
while( $row=mysql_fetch_array($result, MYSQL_NUM) ) {
    $js_array .= $row[0]; 
    $js_array .= ",";
}
$js_array{ strlen($js_array)-1 } = ']';

 ?>

<script>
var cities = <?php echo  $js_array; ?>
for(var i=0; i<4;i++)
alert(cities.length);

</script> 

Answer 1

The simplest approach is converting to JSON with json_encode:

// with $js_array being a true array
var cities = <?php echo json_encode($js_array)?>;

Note, that there are esoteric cases, where this solution might not work. On the other hand, the advantage is, that json_encode takes over all quoting needs.