When they copy the JavaScript to the editor and submit script works on front end of the website.

When you open that record JavaScript disappears from the editor but it still on  front end of the website.

Example:

<script language="JavaScript">SCRIPT_NAME ("0","/Images/button_login.gif") </script>

Example:

But I still have a problem with JavaScript not working on front end of the site.

I add a custom button which opens a window. There I display library of scripts. When user selects the script I’m using JavaScript IPI to copy script in the editor. All that is works well.
When user submit the record that script not working. Script still in the editor and when I view html source on front end of the site JavaScript is there but not working.
Script Example:

<script>

var mydate=new Date()
var year=mydate.getYear()
if (year < 1000)
year+=1900
var day=mydate.getDay()
var month=mydate.getMonth()
var daym=mydate.getDate()
if (daym<10)
daym="0"+daym
var dayarray=new Array("Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday")
var montharray=new Array("January","February","March","April","May","June","July","August","September","October","November","December")
document.write("<small><font color='000000' face='Arial'><b>"+dayarray[day]+", "+montharray[month]+" "+daym+", "+year+"</b></font></small>")

</script>