HTML tags

Code

{source}<span style="color:red">This text should be red!</span>{/source}

Result

This text should be red!

HTML tags (with double square brackets)

If your editor has problems saving tags entered in the WYSIWYG view, and strips these upon saving, then you can use the double bracket syntax for tags.
So [[tag]] instead of <tag>.

Code

{source}[[span style="color:red"]]This text should be red![[/span]]{/source}

Result

This text should be red!

JavaScript

Code

{source}
<script type="text/javascript">
    document.write('This text is placed through <strong>JavaScript</strong>!');
</script>
{/source}

Result

PHP

Code

{source}
<?php
    echo 'This text is placed through <strong>PHP</strong>!';
?>
{/source}

Result

This text is placed through PHP!

Combined (HTML, JavaScript and PHP)

Code

{source}
<span style="color:red">This text should be red!</span>
<br />
<script type="text/javascript">
    document.write('This text is placed through <strong>JavaScript</strong>!');
</script>
<?php
    echo '<p>';
    echo 'This text is placed through <strong>PHP</strong>!';
    echo '</p>';
?>
{/source}

Result

This text should be red!

This text is placed through PHP!