如何将php变量赋给JS变量

Question

    <html>
    <head>

    <script type="text/javascript">
    var t;
 alert(t);
    </script>

    </head>

    <body>

    <?php

    $dbhost = 'localhost';
    $dbuser = 'root';
    $dbpass = 'pass';

    $t_id = 6;

    $con = new PDO("mysql:host=$dbhost;dbname=testing",$dbuser,$dbpass);               

    $q = $con-> prepare("query");

    $q -> bindParam(1,$t_id);

    $q -> execute();
    $res = $q->fetchAll();

    foreach($res as $r)
    {
            $ab = $r[0];
        $abc = $r[1];
    }          
     echo $ab;
     echo $abc;  
    ?>
    <script type="text/javascript">
    t = <?php echo $abc;?>;

    </script>
    </body>
    </html>

当我在分配php变量后提醒"t“变量时，它工作得很好。但是我想在页面的头部分使用t。实际上，我只想从DB中设置JS变量。怎么做？

Answer 1

 <html>
    <head>
//move your php code to head of the page
    <?php

    $dbhost = 'localhost';
    $dbuser = 'root';
    $dbpass = 'pass';

    $t_id = 6;

    $con = new PDO("mysql:host=$dbhost;dbname=testing",$dbuser,$dbpass);               

    $q = $con-> prepare("query");

    $q -> bindParam(1,$t_id);

    $q -> execute();
    $res = $q->fetchAll();

    foreach($res as $r)
    {
            $ab = $r[0];
        $abc = $r[1];
    }          
     echo $ab;
     echo $abc;  
    ?>

    <script type="text/javascript">
       var t;
       t = <?php echo $abc;?>; //add the database variable here you want to use      
       alert(t);
    </script>

    </head>
    <body>       

    </body>
    </html>

让我们知道它是否仍然令人困惑

Answer 2

希望它能帮到你

<script type="text/javascript">
    var t = "<?php echo $abc;?>"; //if not initialised variable t before use var
</script>

Answer 3

试着像

<script type="text/javascript">
    t = '<?php echo $abc;?>';
</script>