CakePHP向脚本标记添加异步

In Google's PageSpeed reports that there are some Blocking Javascript required to be async. From this article I knew that I have to place async attribute to my scripts tag:

<script async src="http://third-party.com/resource.js"></script>

In cakePHP, I don't able to achieve this exactly, I just able to get:

<script async="async" src="http://third-party.com/resource.js"></script>

Using the Html's script method as follows:

$html->script(array('jsfile1', 'jsfile2'), array('async' => 'async'));

I tried array('async') but it prints out 0='0' in the script tag

How could I make it print just async in the script tag. Also, how could I make it available in the link tag of css too?

Notice: I use CakePHP 1.3x

Checking the source code indicates that there is no way to implement such tag as it's obvious that the format of attributes is %s="%s".

If you really need this I think the easiest way now is to provide your own customized HtmlHelper by extending the core HtmlHelper, and overwrite the _formatAttribute function:

Note: this is for CakePHP 1.3.x only and it's pretty messy as it can't specify className in the helpers array. CakePHP 2.x provides a cleaner way to overwrite default core helper with ease, but it's not what OP wanted so I'll not put it up here

1. Create app/views/helpers/custom_html.php:

   <?php
   App::import('Helper', 'Html');
   class CustomHtmlHelper extends HtmlHelper {
       function __formatAttribute($key, $value, $escape = true) {
           if (in_array($key, array('async', 'defer'))) {
               return $key;
           }
           return parent::__formatAttribute($key, $value, $escape);
       }
   }
   

2. In your app_controller.php or whatever main controller that need this, use the CustomHtmlHelper by:

   var $helpers = array('CustomHtml');
   

3. And in your view, you can now start using async or defer tag. Feel free to extend this array if you see fit.

   echo $this->CustomHtml->script('test', array('async' => 'async'));