PHP - Use of undefined constant
<p>I am getting following errors. I have tried many things but it is not working. It is a login with Paypal payment system it is working when I tested on Paypal however on code script failing.</p>

<pre><code>&lt;script&gt;
    paypal.use( ["login"], function(login) {
    login.render ({
        'appid': '&lt;b&gt;Notice&lt;/b&gt;: Use of undefined constant client_id - assumed 'client_id' in &lt;b&gt;/home/yu/public_html/yu.com/catalog/view/theme/beaute/template/module/pp_login.tpl&lt;/b&gt; on line &lt;b&gt;8&lt;/b&gt;client_id',
        'authend': '&lt;b&gt;Notice&lt;/b&gt;: Use of undefined constant sandbox - assumed 'sandbox' in &lt;b&gt;/home/yu/public_html/yu.com/catalog/view/theme/beaute/template/module/pp_login.tpl&lt;/b&gt; on line &lt;b&gt;9&lt;/b&gt;sandbox',
        'scopes': '&lt;b&gt;Notice&lt;/b&gt;: Use of undefined constant scopes - assumed 'scopes' in &lt;b&gt;/home/yu/public_html/yu.com/catalog/view/theme/beaute/template/module/pp_login.tpl&lt;/b&gt; on line &lt;b&gt;10&lt;/b&gt;scopes',
        'containerid': 'pp_login_container',
        'locale': '&lt;b&gt;Notice&lt;/b&gt;: Use of undefined constant locale - assumed 'locale' in &lt;b&gt;/home/yu/public_html/yu.com/catalog/view/theme/beaute/template/module/pp_login.tpl&lt;/b&gt; on line &lt;b&gt;12&lt;/b&gt;locale',
        'theme': '&lt;b&gt;Notice&lt;/b&gt;: Use of undefined constant button_colour - assumed 'button_colour' in &lt;b&gt;/home/yu/public_html/yu.com/catalog/view/theme/beaute/template/module/pp_login.tpl&lt;/b&gt; on line &lt;b&gt;13&lt;/b&gt;button_colour',
        'returnurl': '&lt;b&gt;Notice&lt;/b&gt;: Use of undefined constant return_url - assumed 'return_url' in &lt;b&gt;/home/yu/public_html/yu.com/catalog/view/theme/beaute/template/module/pp_login.tpl&lt;/b&gt; on line &lt;b&gt;14&lt;/b&gt;return_url'
    });
});
    &lt;/script&gt;
</code></pre>

<p><strong>Here is the code causing error.</strong></p>

<pre><code>  &lt;div class="panel panel-default"&gt;
  &lt;div class="panel-body" style="text-align: right;"&gt;
    &lt;span id="pp_login_container"&gt;&lt;/span&gt;
   &lt;script src="https://www.paypalobjects.com/js/external/api.js"&gt;&lt;/script&gt;
    &lt;script&gt;
    paypal.use( ["login"], function(login) {
    login.render ({
        'appid': '&lt;?php if (isset($pp_login_client_id)) echo $pp_login_client_id;else echo client_id; ?&gt;',
        'authend': '&lt;?php if (isset($pp_login_sandbox)) echo $pp_login_sandbox;else echo sandbox; ?&gt;',
        'scopes': '&lt;?php if (isset($pp_login_scopes)) echo $pp_login_scopes;else echo scopes; ?&gt;',
        'containerid': 'pp_login_container',
        'locale': '&lt;?php if (isset($pp_login_locale)) echo $pp_login_locale;else echo locale; ?&gt;',
        'theme': '&lt;?php if (isset($pp_login_button_colour)) echo $pp_login_button_colour;else echo button_colour; ?&gt;',
        'returnurl': '&lt;?php if (isset($pp_login_return_url)) echo $pp_login_return_url;else echo return_url; ?&gt;'
    });
});
    &lt;/script&gt;
  &lt;/div&gt;
&lt;/div&gt;
</code></pre>