Javascript in Posts
To use Javascript inside of posts in WordPress, you need to take a few more steps. Odds are that this usage is for one or only a few instances, so adding the script to the header would be unnecessary.
For the occasional or one time use of Javascript, you need to put the script into a Javascript file and then call it out from within the post. Make sure that each script is defined by its function name such as:
function updatepage(){var m="Page updated "+document.lastMo.......}
To include a Javascript inside a post, you need to combine both the call to the script file with the call to the Javascript itself.
<script type="text/javascript" src="/scripts/updatepage.js"></script>
<script type="text/javascript">
<!--
updatepage();
//--></script>
If the src attribute of your javascript tag is being stripped out you need to turn off the rich editor (from the dashboard go to Users > Personal Options). If you are using the rich editor the javascript tag's src attribute may be stripped out even when manually editing in the HTML popup window.