Javascript Have description限制页面上的字符数。PHP

好的，我在一个PHP网站上工作，我在图片下有产品的描述，我需要做的是限制页面上的字符数量，并添加一个单击此处或。。让观众直接进入该产品页面以查看完整描述。仅供参考，这是我到目前为止对PHP非常陌生的内容。所以问题是我是使用PHP还是javascript，或者两者都使用，以及我如何做到这一点

<?php
// Include need php scripts
require_once ("Includes/simplecms-config.php");
require_once ("Includes/connectDB.php");
include ("Includes/header.php");
if (!empty($_GET['cat'])) {
    $category = $_GET['cat'];
    $query = mysqli_query($db, "SELECT * FROM products WHERE category = '".$category."'");
} else {
    $query = mysqli_query($db, "SELECT * FROM products");
}
if (!$query) {
    die('Database query failed: ' . $query->error);
} 
?>
<section>
    <div id="productList">
        <?php
        $row_count = mysqli_num_rows($query);
        if ($row_count == 0) {
            echo '<p style="color:red">There are no images uploaded for this category</p>';
        } elseif ($query) {
            while($products = mysqli_fetch_array($query)){             
                $file = $products['image'];
                $product_name = $products['product'];
                $image_id = $products['id'];
                $price = $products['price'];
                $desc = $products['description'];
                echo '<div class="image_container">';
                echo '<a href="viewProduct.php?id=' . $image_id . '"><p><img src="Images/products/'.$file.'" alt="'.$product_name.'" height="250" /></p>';
                echo $product_name . "</a><br>$" . $price . "<br>" . $desc;
                echo '</div>';
                if (is_admin()){
                    echo "<a href='deleteproduct.php'><button>delete</button></a>";
                }
            } 
        } else {
            die('There was a problem with the query: ' .$query->error);             
        } 
        mysqli_free_result($query);     
        ?>
    </div>
</section>
<?php include ("Includes/footer.php"); ?>

使用strlen和substr我们可以实现这一点

$length = 150
$x = 'string';

 if(strlen($x)<=$length)
  {
    echo $x;
  }
  else
  {
    $y=substr($x,0,$length) . '...';
    echo $y;
  }

---

这看起来并不粗鲁，但您可能想进一步学习PHP和Javascript。Udemy有一些很棒的便宜菜。。还有其他人在那里。。我决不赞成我的。。但在我参加的许多在线课程中，它们是最好的。。除非你想花几千