我有一个变量在PHP,我需要它的值在我的JavaScript代码。我怎么能把我的变量从PHP到JavaScript?

我有这样的代码:

<?php
$val = $myService->getValue(); // Makes an API and database call

在同一页上,我有JavaScript代码,需要$val变量的值作为参数传递:

<script>
    myPlugin.start($val); // I tried this, but it didn't work
    <?php myPlugin.start($val); ?> // This didn't work either
    myPlugin.start(<?=$val?>); // This works sometimes, but sometimes it fails
</script>

当前回答

<?php

    $val = $myService->getValue(); // Makes an API and database call

    echo "
        <script>
            myPlugin.start({$val});
        </script> ";

?>

其他回答

诀窍是这样的:

下面是使用该变量的“PHP”: <?php $name = 'PHP变量'; 回声的< >脚本; 返回'var name = '。json_encode()美元。';; 回声的> < /脚本; ? > 现在你有了一个名为“name”的JavaScript变量,下面是使用该变量的JavaScript代码: <脚本> console.log(“我无处不在”+名字); > < /脚本

只需使用以下方法之一。

<script type="text/javascript">
var js_variable  = '<?php echo $php_variable;?>';
<script>

OR

<script type="text/javascript">
    var js_variable = <?php echo json_encode($php_variable); ?>; 
</script>

将数据转换为JSON 调用AJAX来接收JSON文件 将JSON转换为Javascript对象

例子:

步骤1

<?php

   $servername = "localhost";
   $username = "";
   $password = "";
   $dbname = "";
   $conn = new mysqli($servername, $username, $password, $dbname);

   if ($conn->connect_error) {
      die("Connection failed: " . $conn->connect_error);
   } 

   $sql = "SELECT id, name, image FROM phone";
   $result = $conn->query($sql);

   while($row = $result->fetch_assoc()){ 
      $v[] = $row;    
   }

  echo json_encode($v);

  $conn->close();
?>

步骤2

function showUser(fnc) {
   var xhttp = new XMLHttpRequest();

   xhttp.onreadystatechange = function() {
      if (this.readyState == 4 && this.status == 200) {
         // STEP 3    
         var p = JSON.parse(this.responseText);
      }
   }
}

我想出了一个简单的方法来分配JavaScript变量使用PHP。

它使用HTML5数据属性来存储PHP变量,然后在页面加载时分配给JavaScript。

例子:

<?php
    $variable_1 = "QNimate";
    $variable_2 = "QScutter";
?>
    <span id="storage" data-variable-one="<?php echo $variable_1; ?>" data-variable-two="<?php echo $variable_2; ?>"></span>
<?php

下面是JavaScript代码

var variable_1 = undefined;
var variable_2 = undefined;

window.onload = function(){
    variable_1 = document.getElementById("storage").getAttribute("data-variable-one");
    variable_2 = document.getElementById("storage").getAttribute("data-variable-two");
}
<?php

    $val = $myService->getValue(); // Makes an API and database call

    echo "
        <script>
            myPlugin.start({$val});
        </script> ";

?>