从数据库中获取数据并且更新不起作用

我有这个用于 user-edit.php 的代码我需要用这个代码从数据库中获取用户数据并将其显示到文本框，并且用户能够编辑文本框值并更新数据库

<?php
    include("config/session.php");
    include("config/connection.php");
    $user_id =  $_SESSION['LOGGED_USER_ID']; 
?>

<?php 
    $sql_query = "SELECT * FROM table_users WHERE `SNo` = '$user_id'"; 
    $query = mysql_query($sql_query);
    //$i = 1;
    $fetch = mysql_fetch_assoc($query);

    //$user_id = $_GET['id'];   

?>      
<form name="form1" action="<?php echo $_SERVER['PHP_SELF']; ?>" method="POST" >
    <fieldset>

        <p>
            <label for="simple-input" >User Name</label>
            <input type="text" id="UserName" class="round default-width-input" autofocus name="UserName" value="<?php echo $fetch['UserName'];?>" readonly="readonly" />
        </p>
        <p>
            <label for="simple-input" >Password</label>
            <input type="text" id="pass_word" class="round default-width-input" autofocus name="pass_word" value="<?php echo $fetch['pass_word'];?>" />
        </p>
        <p>
            <label for="simple-input" >Email ID</label>
            <input type="text" id="Email" class="round default-width-input" autofocus name="Email" value="<?php echo $fetch['Email'];?>" />

        </p>
        <p>
            <label for="simple-input" >Website</label>
            <input type="text" id="website" class="round default-width-input" autofocus name="website" value="<?php echo $fetch['website'];?>" />
        </p>


    </fieldset>

    <input type="submit" class="btn btn-primary btn-large" name="form_submit" value="Update Data"/> 

</form>

<?php

if(isset($_POST['form_submit']))
{
    "UPDATE `table_users` SET `pass_word` =  '".$_POST['pass_word']."',`Email` =  '".$_POST['Email']."',`website` =  '".$_POST['website']."', WHERE `SNo` = '$user_id'";

    // sql query for update data into database
    if(mysql_query($sql_query))
     {

      echo '<script type="text/javascript">';
      echo 'alert("Data Are Updated Successfully");';
      echo '</script>';

     }
     else
     {

      echo '<script type="text/javascript">';
      echo 'alert("error occured while updating data");';
      echo '</script>';
    }
    }
?>

        </div>
    </div>                          
</div>

已经使用了几个小时，但数据仍未更新到 mysql 数据库，尝试了多种方法，但文本框值仍然无法更新数据库，请帮助