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| |
| <html> |
| <head> |
| <meta name="viewport" content="width=device-width, initial-scale=1"> |
| <title>Convert Meta Tags</title> |
| <link rel="stylesheet" href="doc.css"> |
| </head> |
| <body> |
| <!--#include virtual="_header.html" --> |
| |
| |
| <div id=content> |
| <h1>Convert Meta Tags</h1> |
| <h2>Configuration</h2> |
| <p> |
| The 'Convert Meta Tags' filter is enabled by specifying: |
| <dl> |
| <dt>Apache:<dd><pre class="prettyprint" |
| >ModPagespeedEnableFilters convert_meta_tags</pre> |
| <dt>Nginx:<dd><pre class="prettyprint" |
| >pagespeed EnableFilters convert_meta_tags;</pre> |
| </dl> |
| <p> |
| in the configuration file, but it is also enabled automatically by the core |
| filter set. |
| </p> |
| |
| <h2>Description</h2> |
| <p> |
| The 'Convert Meta Tags' filter adds a response header that matches each meta |
| tag with an http-equiv attribute. For example, HTML |
| <pre class="prettyprint" |
| ><meta http-eqiv="Content-Type" content="text/html; charset=UTF-8"></pre> |
| would add an HTTP header: |
| <pre class="prettyprint" |
| >Content-Type: text/html; charset=UTF-8</pre> |
| in the response headers. |
| </p> |
| <p> |
| The original tag is left unchanged. |
| </p> |
| <p> |
| Certain http-equiv meta tags, specifically those that specify content-type, |
| require a browser to reparse the html document if they do not match the headers. |
| By ensuring that the headers match the meta tags, these reparsing delays are |
| avoided. |
| </p> |
| |
| <h2>Risks</h2> |
| <p> |
| This filter is considered minimal risk because at this time, |
| Content-Type is the only <code>http-equiv</code> value that is transformed into |
| an HTTP header. Other http-equiv values have been found to have unexpected semantic |
| implications when transformed to HTTP. |
| </p> |
| |
| </div> |
| <!--#include virtual="_footer.html" --> |
| </body> |
| </html> |
