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Every time I edit a WordPress post or page that has a google map embedded in it - useing the "visual" edit mode - wordpress deletes part of the data.

for example: this

<iframe width="425" height="350" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src="http://maps.google.com/maps/ms?ie=UTF8&amp;hl=en&amp;msa=0&amp;msid=212526618623367333770.00049b7dc074f6426719d&amp;t=h&amp;ll=34.926059,-81.964874&amp;spn=0.300106,0.458336&amp;output=embed"></iframe><br /><small>View <a href="http://maps.google.com/maps/ms?ie=UTF8&amp;hl=en&amp;msa=0&amp;msid=212526618623367333770.00049b7dc074f6426719d&amp;t=h&amp;ll=34.926059,-81.964874&amp;spn=0.300106,0.458336&amp;source=embed" style="color:#0000FF;text-align:left">1825 Spartanburgh Map</a> in a larger map</small>

turns into

<small>View <a style="color: #0000ff; text-align: left;" href="http://maps.google.com/maps/ms?ie=UTF8&amp;hl=en&amp;msa=0&amp;msid=212526618623367333770.00049b7dc074f6426719d&amp;ll=34.926059,-81.943846&amp;spn=0.300106,0.416279&amp;source=embed">1825</a> in a larger map</small>

Which does not render the map at all.

This does not happen when I edit in "html" mode.

How can I prevent Wordpress from altering this embed code?

share|improve this question
up vote 3 down vote accepted

The issue is WordPress' core configuration of TinyMCE, which strips IFRAME tags.

You can modify this configuration, to allow IFRAME tags, by hooking into tiny_mce_before_init. For example, the following code will prevent TinyMCE from stripping IFRAME, PRE, and DIV tags:

function mytheme_tinymce_config( $init ) {

// Change code cleanup/content filtering config

    // Don't remove line breaks
    $init['remove_linebreaks'] = false; 
    // Convert newline characters to BR tags
    $init['convert_newlines_to_brs'] = true; 
    // Preserve tab/space whitespace
    $init['preformatted'] = true; 
    // Add to list of formats to remove with Remove Format button
    $init['removeformat_selector'] = 'b,strong,em,i,span,ins,del,h1,h2,h3,h4,h5,h6,pre';
    // Do not remove redundant BR tags
    $init['remove_redundant_brs'] = false;

// Add to list of valid HTML elements (so they don't get stripped)

    // IFRAME
    $valid_iframe = 'iframe[id|class|title|style|align|frameborder|height|longdesc|marginheight|marginwidth|name|scrolling|src|width]';
    // PRE
    $valid_pre = 'pre[id|name|class|style]';
    // DIV
    $valid_div = 'div[align<center?justify?left?right|class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style|title]';

    // Concatenate 
    $cbnet_valid_elements = $valid_iframe . ',' . $valid_pre . ',' . $valid_div;

    // Add to extended_valid_elements if it alreay exists
    if ( isset( $init['extended_valid_elements'] ) ) {
        $init['extended_valid_elements'] .= ',' . $cbnet_valid_elements;
    } else {
        $init['extended_valid_elements'] = $cbnet_valid_elements;

// Pass $init back to WordPress
    return $init;
add_filter('tiny_mce_before_init', 'mytheme_tinymce_config');

See here for the full list of configurable options.

share|improve this answer
The page you linked to says that the script must be put in the "HEAD element of a document." Should I add <head></head> to every page? (yes Im a novice) – Dale May 15 '11 at 3:27
No, you update the $init array parameters. – Chip Bennett May 15 '11 at 3:54
How is that done? Say the word and Ill make a separate question for that. – Dale May 15 '11 at 4:21
See edited function, which now includes some examples of how to change $init array parameters. – Chip Bennett May 15 '11 at 17:27
@Chip Bennett, where do i go specifically to modify this configuration? – user5666 May 25 '11 at 6:32

I don't know for certain, but I think it may be related to the allowed tags for posts. See my question from a few days ago. Basically wordpress will filter out tags that are not allowed. So for example you could prevent script tags. You also have to specify what parameters are allowed. So for instance you could allow an img tag with the src attribute, but not the alt attribute.

What are allowedposttags and allowedtags?

share|improve this answer
I should have also pointed out that you can add the code from that link, modified for your use case of course, to your functions.php file. – mrtsherman May 14 '11 at 18:04

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