Can a page contain php code?

Question

I am trying to use the following line of PHP code in one of my pages:

<input name="from" id="from" value="<?php echo $_GET['from'];?>" type="text" />

But instead of displaying an empty "from" input field (before typing anything into it), it displays <?php echo $_GET['from'];.

Am I missing something?

Clarification: I am entering this line of PHP code (in addition to some HTML) from the Admin's Edit Page (the HTML tab of course, not the Visual one).

Answer 1

You can't use PHP in the WordPress back-end editor. Maybe with a plugin you can, but not out of the box.

The easiest solution for this is creating a shortcode. Then you can use something like [input type="text" name"from"] in your editor.

function input_func( $atts ) {
    extract( shortcode_atts( array(
        'type' => 'text',
        'name' => '',
    ), $atts ) );

    return '<input name="' . $name . '" id="' . $name . '" value="' . (isset($_GET['from']) && $_GET['from'] ? $_GET['from'] : '') . '" type="' . $type . '" />';
}
add_shortcode( 'input', 'input_func' );

See http://codex.wordpress.org/Shortcode_API

Answer 2

Yes, post content are sanitized : all characters are converted to HTML equivalent and therefore no code could be executed. There is plugins that allows to execute code from post content, but it's bad security. You would better explore shortcodes (that create line of pseudo-code leading to execute real PHP code) or customizing theme files.

Shortcode http://codex.wordpress.org/Shortcode_API

Answer 3

Are you trying to enter this form field/PHP output in the post content?

If so, then: no, you cannot do that. WordPress will strip both the form field AND will sanitize the PHP output.

You need to add such content functionally, i.e. directly in the template file, or else via action/filter hook callback.