_fcksavedurl ????

Why am is fckeditor inserting these _fcksavedurl= into my links?? I paste the following code in the source view of the editor...

<script type="text/javascript">
document.write("<a href=\"mailto:")
document.write("support-de")
document.write("@")
document.write("test.com\">")
document.write("support-de")
document.write("@")
document.write("test.com")
document.write("<\/a>")
</script>

and then fceditor changes it to ..

><script type="text/javascript">
document.write("<a href=\"mailto:")
_fcksavedurl="\"mailto:")
" _fcksavedurl="\"mailto:")
" document.write("support-de")
document.write("@")
document.write("test.com\">")
document.write("support-de")
document.write("@")
document.write("test.com")
document.write("<\/a>")
</script>

How can I precent this?