Google AMP - 表单

本章解释如何在Google AMP中使用表单。

请注意，表单标签与标准HTML中的表单标签相同。由于AMP对表单的使用添加了特殊的限制，因此我们需要添加amp-form JavaScript文件才能使用表单。

amp-form脚本

<script async custom-element = "amp-form" 
   src = "https://cdn.ampproject.org/v0/ampform-0.1.js"></script>

要在AMP页面中使用表单，我们需要在.html文件中包含上述脚本。amp-form JavaScript文件支持**http**和**xmlhttprequest**提交表单。使用HTTP请求会重新加载页面，而使用**xmlhttprequest**则不会重新加载页面，类似于ajax请求。

AMP中的表单标签

For xmlhttprequest :
<form method = "post" class = "p2" action-xhr = "submitform.php" target = "_top">
   //Input fields here
</form>

For http :
<form method = "post" class = "p2" action = "submitform.php" target = "_top">
   //Input fields here
</form>

Amp-form 提供了特殊的属性，即submit-error和submit-success，用于处理表单提交时的错误和成功。

示例

下面显示了一个amp-form示例：

<!doctype html>
<html amp lang = "en">
   <head>
      <meta charset = "utf-8">
      <script async src = "https://cdn.ampproject.org/v0.js"></script>
      <title>Google AMP - Form</title>
      <link rel = "canonical" href = "ampform.html">
      <meta name = "viewport" conten t = "width = device-width,
         minimum-scale = 1,initialscale = 1">
      
      <style amp-boilerplate>
         body{
            -webkit-animation:
            -amp-start 8s steps(1,end) 0s1 normal both;-moz-animation:
            -amp-start 8s steps(1,end) 0s 1 normal both;-msanimation:
            -amp-start 8s steps(1,end) 0s 1 normal both;animation:
            -amp-start 8s steps(1,end) 0s 1 normal both
         }
         @-webkit-keyframes 
         -ampstart{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes 
         -ampstart{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes 
         -ampstart{from{visibility:hidden}to{visibility:visible}}@-o-keyframes 
         -ampstart{from{visibility:hidden}to{visibility:visible}}@keyframes 
         -ampstart{from{visibility:hidden}to{visibility:visible}}  
      </style>
         <noscript>
            <style amp-boilerplate>
               body{
                  -webkit-animation:none;
                  -moz-animation:none;
                  -msanimation:none;
                  animation:none
               }
            </style>
         </noscript>
      <script async custom-element = "amp-form"
         src = "https://cdn.ampproject.org/v0/amp-form-0.1.js">
      </script>
      <script async custom-template = "amp-mustache"
         src = "https://cdn.ampproject.org/v0/amp-mustache-0.2.js">
      </script>
      <style amp-custom>
         form.amp-form-submit-success [submit-success],
         form.amp-form-submit-error [submit-error]{
            margin-top: 16px;
         }
         form.amp-form-submit-success [submit-success] {
            color: white;
            background-color:gray;
         }
         form.amp-form-submit-error [submit-error] {
            color: red;
         }
         form.amp-form-submit-success.hide-inputs > input {
            display: none;
         }
      </style>
   </head>
   <body>
      <h3>Google AMP - Form</h3>
      <form method = "post" 
         class = "p2" 
         action-xhr = "submitform.php" 
         target = "_top">
         <p>AMP - Form Example</p>
         <div>
            <input type = "text" name = "name" placeholder = "Enter 
               Name" required><br/><br/>
            <input type = "email" name = "email" 
            placeholder = "Enter Email" required>
            <br/>
            <br/>
         </div>
         
         <input type = "submit" value = "Submit">
         <div submit-success>
            <template type = "amp-mustache">
               Form Submitted! Thanks {{name}}.
            </template>
         </div>
         
         <div submit-error>
            <template type = "amp-mustache">
               Error! {{name}}, please try again.
            </template>
         </div>
      </form>
   </body>
</html>

输出

执行上面显示的代码后，您将看到如下所示的结果：

现在，输入详细信息并单击“提交”按钮。显示的输出屏幕如下所示：

请注意，我们使用了amp-mustache进行数据绑定。该表单使用action-xhr（即xmlhttprequest）提交表单。我们使用了**submitform.php**文件，该文件以JSON格式返回数据。

<form method = "post" class = "p2" action-xhr = "submitform.php" 
   target = "_top">
</form>

submitform.php

<?php
   if(!empty($_POST)){
      $domain_url = (isset($_SERVER['HTTPS']) ? "https" : "http") .      "://$_SERVER[HTTP_HOST]";
      header("Content-type: application/json");
      header("AMP-Access-Control-Allow-Source-Origin: " . $domain_url);
      header("Access-Control-Expose-Headers: AMP-Access-Control-Allow-Source-Origin");
      $myJSON = json_encode($_POST);
      echo $myJSON;
   }
?>

为了使表单能够使用xmlhttprequest工作，我们需要根据CORS规范添加标头。下面显示了添加到submitform.php的响应标头的详细信息：

为了使表单正常工作，我们需要添加诸如值为**AMP-Access-Control-Allow-Source-Origin**的**access-control-expose-headers**标头和**amp-access-control-allow-source-origin** - **https://:8080**。

请注意，我们使用的是php文件和apache服务器。在php文件中，我们添加了如下所示的必需标头：

<?php

   if(!empty($_POST)){
      $domain_url = (isset($_SERVER['HTTPS']) ? "https" : "http") .  "://$_SERVER[HTTP_HOST]";
      header("Content-type: application/json");
      header("AMP-Access-Control-Allow-Source-Origin: " . $domain_url);
      header("Access-Control-Expose-Headers: AMP-Access-Control-Allow-Source-Origin");
      $myJSON = json_encode($_POST);
      echo $myJSON;
   }
   ?
?>

如果我们使用普通的http请求，页面将重新加载，如下所示：

对于http请求，我们使用了如下所示的表单：

<form method = "GET" class = "p2" action = "submitform.php" 
   target = "_top">
</form>

示例

请观察以下代码以更好地理解：

<!doctype html>
<html amp lang = "en">
   <head>
      <meta charset = "utf-8">
      <script async src = "https://cdn.ampproject.org/v0.js"></script>
      <title>Google AMP - Form</title>
      <link rel = "canonical" href = "ampform.html">
      <meta name = "viewport" content = "width = device-width,minimum-scale = 1,initialscale = 1">
      
      <style amp-boilerplate>
         body{
            -webkit-animation:
            -amp-start 8s steps(1,end) 0s1 normal both;-moz-animation:
            -amp-start 8s steps(1,end) 0s 1 normal both;-msanimation:
            -amp-start 8s steps(1,end) 0s 1 normal both;animation:
            -amp-start 8s steps(1,end) 0s 1 normal both
         }
         @-webkit-keyframes 
         -ampstart{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes 
         -ampstart{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes 
         -ampstart{from{visibility:hidden}to{visibility:visible}}@-o-keyframes 
         -ampstart{from{visibility:hidden}to{visibility:visible}}@keyframes 
         -ampstart{from{visibility:hidden}to{visibility:visible}}
      </style>
      <noscript>
         <style amp-boilerplate>
            body {
               -webkit-animation:none;
               -moz-animation:none;
               -msanimation:none;
               animation:none}
         >/style>
      </noscript>
      
      <script async custom-element = "amp-form"
         src = "https://cdn.ampproject.org/v0/amp-form-0.1.js">
      </script>
      <script async custom-template = "amp-mustache"
         src = "https://cdn.ampproject.org/v0/amp-mustache-0.2.js">
      </script>
      
      <style amp-custom>
         form.amp-form-submit-success [submit-success],
         form.amp-form-submit-error [submit-error]{
            margin-top: 16px;
         }
         form.amp-form-submit-success [submit-success] {
            color: white;
            background-color:gray;
         }
         form.amp-form-submit-error [submit-error] {
            color: red;
         }
         form.amp-form-submit-success.hide-inputs > 
            input {
            display: none;
         }
      </style>
   </head>
   <body>
      <h3>Google AMP - Form</h3>
      <form method = "GET" class = "p2" action = "submitform.php" target = "_top">
         <p>AMP - Form Example</p>
         <div>
            <input type = "text" name = "name" placeholder = "Enter Name" required>
            <br/>
            <br/>
            <input type = "email" name = "email" placeholder = "Enter Email" required>
            <br/>
            <br/>
         <div>
         
         <input type = "submit" value = "Submit">
         <div submit-success>
            <template type = "amp-mustache">
               Form Submitted! Thanks {{name}}.
            </template>
         </div>
         <div submit-error>
            <template type = "amp-mustache">
               Error! {{name}}, please try again.
            </template>
         </div>
      </form>
   </body>
</html>

输出

执行上面显示的代码后，您将看到如下所示的结果：

打印页面