代码示例中“<<< HTML”的含义[重复]

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I am trying to include some javascript for the google analytics ecommerce tracking.

In the example code I see something like this, in which I have replaced the variables with my own.

<?php
 function getTransactionJs(&$order) {
        return <<<HTML
        ga('ecommerce:addTransaction', {
          'id': '{$order->ord_order_numner}',
          'affiliation': 'Marcella',
          'revenue': '{$order->total_payment}',
          'shipping': '0',
          'tax': '0'
        });
        HTML;
    }


echo getTransactionJs($order);
 ?>

However I met with a syntax error. May I ask what is the meaning of

return <<<HTML

Thanks in advance!

</div>

It’s PHP’s Heredoc syntax. I’m not a fan of it though.

It's a way to define a string on multiple lines. Your string begin juste after the <<<HTML and ends at HTML; The HTML word can be replaced by whatever you want.

See Heredoc syntax.

As suggested read the manual, but consider not to use this kind of syntax.

To make your life easier - in most cases the problem is with text indenting.

HTML;

Must be at the start of the line not indented!